US20030086535A1 - Multimodality imaging phantom and process for manufacturing said phantom - Google Patents
Multimodality imaging phantom and process for manufacturing said phantom Download PDFInfo
- Publication number
- US20030086535A1 US20030086535A1 US10/010,886 US1088601A US2003086535A1 US 20030086535 A1 US20030086535 A1 US 20030086535A1 US 1088601 A US1088601 A US 1088601A US 2003086535 A1 US2003086535 A1 US 2003086535A1
- Authority
- US
- United States
- Prior art keywords
- layer
- phantom
- tissue mimicking
- mimicking material
- container
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Abandoned
Links
- 238000003384 imaging method Methods 0.000 title claims abstract description 86
- 238000000034 method Methods 0.000 title claims abstract description 40
- 230000008569 process Effects 0.000 title claims abstract description 15
- 238000004519 manufacturing process Methods 0.000 title claims abstract description 12
- 239000000463 material Substances 0.000 claims abstract description 97
- 229920001817 Agar Polymers 0.000 claims abstract description 33
- 239000000499 gel Substances 0.000 claims abstract description 26
- 239000008272 agar Substances 0.000 claims abstract description 24
- 239000011521 glass Substances 0.000 claims abstract description 16
- 238000005266 casting Methods 0.000 claims abstract description 12
- 239000003550 marker Substances 0.000 claims description 29
- 238000002844 melting Methods 0.000 claims description 24
- 230000008018 melting Effects 0.000 claims description 24
- 239000003921 oil Substances 0.000 claims description 13
- 238000010521 absorption reaction Methods 0.000 claims description 12
- 239000007788 liquid Substances 0.000 claims description 10
- 229910045601 alloy Inorganic materials 0.000 claims description 9
- 239000000956 alloy Substances 0.000 claims description 9
- 239000012778 molding material Substances 0.000 claims description 9
- 239000007787 solid Substances 0.000 claims description 9
- 239000010690 paraffinic oil Substances 0.000 claims description 8
- 239000004816 latex Substances 0.000 claims description 7
- 229920000126 latex Polymers 0.000 claims description 7
- 238000009792 diffusion process Methods 0.000 claims description 4
- 238000010438 heat treatment Methods 0.000 claims description 3
- 229910001092 metal group alloy Inorganic materials 0.000 claims description 3
- 239000011248 coating agent Substances 0.000 claims description 2
- 238000000576 coating method Methods 0.000 claims description 2
- 238000000465 moulding Methods 0.000 claims description 2
- 238000011156 evaluation Methods 0.000 abstract description 10
- 230000002792 vascular Effects 0.000 abstract description 9
- 230000004087 circulation Effects 0.000 abstract description 7
- 230000004927 fusion Effects 0.000 abstract description 5
- 230000000052 comparative effect Effects 0.000 abstract description 4
- 230000003068 static effect Effects 0.000 abstract description 4
- 238000012360 testing method Methods 0.000 abstract description 4
- 238000012285 ultrasound imaging Methods 0.000 abstract description 4
- 238000012307 MRI technique Methods 0.000 abstract description 2
- 210000001519 tissue Anatomy 0.000 description 40
- 238000002604 ultrasonography Methods 0.000 description 20
- 238000002583 angiography Methods 0.000 description 16
- 239000000203 mixture Substances 0.000 description 13
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 13
- PEDCQBHIVMGVHV-UHFFFAOYSA-N Glycerine Chemical compound OCC(O)CO PEDCQBHIVMGVHV-UHFFFAOYSA-N 0.000 description 12
- 239000012530 fluid Substances 0.000 description 10
- 208000031481 Pathologic Constriction Diseases 0.000 description 6
- 210000001367 artery Anatomy 0.000 description 6
- 239000002872 contrast media Substances 0.000 description 6
- 230000017531 blood circulation Effects 0.000 description 4
- 239000001913 cellulose Substances 0.000 description 4
- 229920002678 cellulose Polymers 0.000 description 4
- 238000002059 diagnostic imaging Methods 0.000 description 4
- 239000002245 particle Substances 0.000 description 4
- NIXOWILDQLNWCW-UHFFFAOYSA-N acrylic acid group Chemical group C(C=C)(=O)O NIXOWILDQLNWCW-UHFFFAOYSA-N 0.000 description 3
- 239000008280 blood Substances 0.000 description 3
- 210000004369 blood Anatomy 0.000 description 3
- 229920001971 elastomer Polymers 0.000 description 3
- PCHJSUWPFVWCPO-UHFFFAOYSA-N gold Chemical compound [Au] PCHJSUWPFVWCPO-UHFFFAOYSA-N 0.000 description 3
- 238000002595 magnetic resonance imaging Methods 0.000 description 3
- 229920001225 polyester resin Polymers 0.000 description 3
- 239000004645 polyester resin Substances 0.000 description 3
- -1 polyethylen Polymers 0.000 description 3
- 238000003325 tomography Methods 0.000 description 3
- 210000003462 vein Anatomy 0.000 description 3
- 229910052688 Gadolinium Inorganic materials 0.000 description 2
- 229910052782 aluminium Inorganic materials 0.000 description 2
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 2
- 230000008901 benefit Effects 0.000 description 2
- 210000004204 blood vessel Anatomy 0.000 description 2
- 230000002490 cerebral effect Effects 0.000 description 2
- 238000010968 computed tomography angiography Methods 0.000 description 2
- UIWYJDYFSGRHKR-UHFFFAOYSA-N gadolinium atom Chemical compound [Gd] UIWYJDYFSGRHKR-UHFFFAOYSA-N 0.000 description 2
- 230000000004 hemodynamic effect Effects 0.000 description 2
- 238000002608 intravascular ultrasound Methods 0.000 description 2
- 230000003902 lesion Effects 0.000 description 2
- 229920000573 polyethylene Polymers 0.000 description 2
- 238000011002 quantification Methods 0.000 description 2
- 210000003625 skull Anatomy 0.000 description 2
- 230000006439 vascular pathology Effects 0.000 description 2
- ZCYVEMRRCGMTRW-UHFFFAOYSA-N 7553-56-2 Chemical compound [I] ZCYVEMRRCGMTRW-UHFFFAOYSA-N 0.000 description 1
- 239000004925 Acrylic resin Substances 0.000 description 1
- 229920000178 Acrylic resin Polymers 0.000 description 1
- 206010002329 Aneurysm Diseases 0.000 description 1
- 200000000007 Arterial disease Diseases 0.000 description 1
- WSFSSNUMVMOOMR-UHFFFAOYSA-N Formaldehyde Chemical compound O=C WSFSSNUMVMOOMR-UHFFFAOYSA-N 0.000 description 1
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 description 1
- 229910000846 In alloy Inorganic materials 0.000 description 1
- VVQNEPGJFQJSBK-UHFFFAOYSA-N Methyl methacrylate Chemical compound COC(=O)C(C)=C VVQNEPGJFQJSBK-UHFFFAOYSA-N 0.000 description 1
- 239000004677 Nylon Substances 0.000 description 1
- 229920005372 Plexiglas® Polymers 0.000 description 1
- 239000004743 Polypropylene Substances 0.000 description 1
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 description 1
- 208000007536 Thrombosis Diseases 0.000 description 1
- 210000000577 adipose tissue Anatomy 0.000 description 1
- 239000010615 agar oil Substances 0.000 description 1
- 239000004411 aluminium Substances 0.000 description 1
- 210000000702 aorta abdominal Anatomy 0.000 description 1
- 230000036770 blood supply Effects 0.000 description 1
- 210000005013 brain tissue Anatomy 0.000 description 1
- 210000001715 carotid artery Anatomy 0.000 description 1
- 239000003795 chemical substances by application Substances 0.000 description 1
- 238000003759 clinical diagnosis Methods 0.000 description 1
- 230000000295 complement effect Effects 0.000 description 1
- 238000002591 computed tomography Methods 0.000 description 1
- 238000013170 computed tomography imaging Methods 0.000 description 1
- 238000010276 construction Methods 0.000 description 1
- 230000003247 decreasing effect Effects 0.000 description 1
- 238000013461 design Methods 0.000 description 1
- 238000011161 development Methods 0.000 description 1
- 238000001035 drying Methods 0.000 description 1
- 239000002961 echo contrast media Substances 0.000 description 1
- 239000000839 emulsion Substances 0.000 description 1
- 239000003822 epoxy resin Substances 0.000 description 1
- 239000004744 fabric Substances 0.000 description 1
- 239000008098 formaldehyde solution Substances 0.000 description 1
- 239000007789 gas Substances 0.000 description 1
- 239000001257 hydrogen Substances 0.000 description 1
- 229910052739 hydrogen Inorganic materials 0.000 description 1
- 238000002513 implantation Methods 0.000 description 1
- 238000002347 injection Methods 0.000 description 1
- 239000007924 injection Substances 0.000 description 1
- 238000011835 investigation Methods 0.000 description 1
- 239000011630 iodine Substances 0.000 description 1
- 229910052740 iodine Inorganic materials 0.000 description 1
- 230000036244 malformation Effects 0.000 description 1
- 239000011159 matrix material Substances 0.000 description 1
- 230000007246 mechanism Effects 0.000 description 1
- 239000007769 metal material Substances 0.000 description 1
- 244000005700 microbiome Species 0.000 description 1
- 238000003801 milling Methods 0.000 description 1
- 230000003278 mimic effect Effects 0.000 description 1
- 238000002156 mixing Methods 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 230000000877 morphologic effect Effects 0.000 description 1
- 229920001778 nylon Polymers 0.000 description 1
- 229920000647 polyepoxide Polymers 0.000 description 1
- 229920000642 polymer Polymers 0.000 description 1
- 229920001155 polypropylene Polymers 0.000 description 1
- 239000000843 powder Substances 0.000 description 1
- 238000002360 preparation method Methods 0.000 description 1
- 230000035755 proliferation Effects 0.000 description 1
- 239000011347 resin Substances 0.000 description 1
- 229920005989 resin Polymers 0.000 description 1
- 238000012552 review Methods 0.000 description 1
- 239000000523 sample Substances 0.000 description 1
- 229910052710 silicon Inorganic materials 0.000 description 1
- 239000010703 silicon Substances 0.000 description 1
- 229920005573 silicon-containing polymer Polymers 0.000 description 1
- 238000007711 solidification Methods 0.000 description 1
- 230000008023 solidification Effects 0.000 description 1
- 241000894007 species Species 0.000 description 1
- 230000036262 stenosis Effects 0.000 description 1
- 208000037804 stenosis Diseases 0.000 description 1
- 230000004936 stimulating effect Effects 0.000 description 1
- 238000003756 stirring Methods 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- 230000007704 transition Effects 0.000 description 1
- 208000019553 vascular disease Diseases 0.000 description 1
- 238000012795 verification Methods 0.000 description 1
- 229910000634 wood's metal Inorganic materials 0.000 description 1
Images
Classifications
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
- A61B6/00—Apparatus or devices for radiation diagnosis; Apparatus or devices for radiation diagnosis combined with radiation therapy equipment
- A61B6/58—Testing, adjusting or calibrating thereof
- A61B6/582—Calibration
- A61B6/583—Calibration using calibration phantoms
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
- A61B8/00—Diagnosis using ultrasonic, sonic or infrasonic waves
- A61B8/58—Testing, adjusting or calibrating the diagnostic device
- A61B8/587—Calibration phantoms
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R33/00—Arrangements or instruments for measuring magnetic variables
- G01R33/20—Arrangements or instruments for measuring magnetic variables involving magnetic resonance
- G01R33/44—Arrangements or instruments for measuring magnetic variables involving magnetic resonance using nuclear magnetic resonance [NMR]
- G01R33/48—NMR imaging systems
- G01R33/58—Calibration of imaging systems, e.g. using test probes, Phantoms; Calibration objects or fiducial markers such as active or passive RF coils surrounding an MR active material
-
- G—PHYSICS
- G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
- G09B—EDUCATIONAL OR DEMONSTRATION APPLIANCES; APPLIANCES FOR TEACHING, OR COMMUNICATING WITH, THE BLIND, DEAF OR MUTE; MODELS; PLANETARIA; GLOBES; MAPS; DIAGRAMS
- G09B23/00—Models for scientific, medical, or mathematical purposes, e.g. full-sized devices for demonstration purposes
- G09B23/28—Models for scientific, medical, or mathematical purposes, e.g. full-sized devices for demonstration purposes for medicine
- G09B23/286—Models for scientific, medical, or mathematical purposes, e.g. full-sized devices for demonstration purposes for medicine for scanning or photography techniques, e.g. X-rays, ultrasonics
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
- A61B5/00—Measuring for diagnostic purposes; Identification of persons
- A61B5/0033—Features or image-related aspects of imaging apparatus classified in A61B5/00, e.g. for MRI, optical tomography or impedance tomography apparatus; arrangements of imaging apparatus in a room
- A61B5/0035—Features or image-related aspects of imaging apparatus classified in A61B5/00, e.g. for MRI, optical tomography or impedance tomography apparatus; arrangements of imaging apparatus in a room adapted for acquisition of images from more than one imaging mode, e.g. combining MRI and optical tomography
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
- A61B5/00—Measuring for diagnostic purposes; Identification of persons
- A61B5/05—Detecting, measuring or recording for diagnosis by means of electric currents or magnetic fields; Measuring using microwaves or radio waves
- A61B5/055—Detecting, measuring or recording for diagnosis by means of electric currents or magnetic fields; Measuring using microwaves or radio waves involving electronic [EMR] or nuclear [NMR] magnetic resonance, e.g. magnetic resonance imaging
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B33—ADDITIVE MANUFACTURING TECHNOLOGY
- B33Y—ADDITIVE MANUFACTURING, i.e. MANUFACTURING OF THREE-DIMENSIONAL [3-D] OBJECTS BY ADDITIVE DEPOSITION, ADDITIVE AGGLOMERATION OR ADDITIVE LAYERING, e.g. BY 3-D PRINTING, STEREOLITHOGRAPHY OR SELECTIVE LASER SINTERING
- B33Y80/00—Products made by additive manufacturing
Definitions
- the present invention relates to a multimodality imaging phantom and a process for manufacturing the same.
- the multimodality imaging phantom is particularly useful for calibrating imaging devices or apparatuses using different imaging modalities.
- vascular diseases i.e. quantification of the vascular lumen geometry
- the techniques are based either on X-rays (X-ray angiography, and computerized tomography (CT)), ultrasonography (B-mode, M-mode, pulsed-wave Doppler, power Doppler, color Doppler, intravascular ultrasound (IVUS)), or on magnetic resonance angiography (MRA) (gradient-recalled echo sequence, phase-contrast, gadolinium enhanced angiography).
- CT computerized tomography
- M-mode ultrasonography
- IVS intravascular ultrasound
- MRA magnetic resonance angiography
- Angiography provides geometrical data on the vessel lumen, whereas IVUS and CT can be used independently or complementary to angiography to investigate the arterial wall morphology and composition.
- Knowledge on the hemodynamics is also of great interest to evaluate the consequences of lesions on blood supply to the tissues perfused by diseased vessels.
- Doppler ultrasound and phase contrast MRA allow to study blood flow, namely to measure blood velocities in the vessels.
- calibration of the medical imaging apparatuses is an essential step required for accurate imaging and evaluation of blood vessels.
- Test objects known as calibration phantoms, are commonly used for this purpose and specific phantoms have been developed to meet the requirements associated to each imaging modality.
- Vascular flow phantoms are ideal tools for such studies since they provide a way of testing the geometric accuracy, with easy reproducibility of the experimental conditions when different modalities are tested. They can also be used to compare the blood flow velocity patterns obtained by ultrasound and MRA. Moreover, it is possible to reproduce vascular pathologies, with a known geometry that can be accurately determined during fabrication, and which can be used as the “gold standard reference” for evaluation of imaging devices. Multimodality phantoms have to meet three major requirements. First, they must be compatible with many if not all the imaging modalities evaluated, i.e. it is necessary that the vessel position can be clearly identified on the images, with no or minimum artifacts in any modality. Second, they should be anthropomorphic, i.e. their geometry should mimic as close as possible the complexity of real human vessels. Finally, they should contain markers visible in all modalities for image calibration, resealing and fusion.
- Multimodality anthropomorphic vascular flow phantoms have been proposed in the recent years using three major techniques: stereolithography, phantoms including real vessels and lost-material casting method.
- stereolithography phantoms including real vessels and lost-material casting method.
- Creasy et al. presented a simple cranial blood flow phantom compatible with X-ray, MRA and CT angiography. It consisted in an acrylic skull filled with a silicone polymer mimicking human brain tissue, which contains the main cerebral vessels.
- the blood- and tissue-mimicking materials had X-ray, ultrasound and MRA properties close to those of blood and human tissues, but polyester resin was found to be a poor ultrasound and MRA tissue-mimicking material.
- Static images were recorded with X-ray angiography, CT, ultrasound and MRA for evaluation of the geometric accuracy of these techniques.
- Velocity images were acquired under steady flow with color Doppler and phase contrast MRA. The two techniques gave flow patterns which qualitatively agreed with each other and with literature data, and measured volume flow-rates were in good agreement (4.4%) with actual values.
- An object of the invention is to provide a multimodality imaging phantom for calibrating an imaging apparatus.
- Another object of the invention is to provide a process for manufacturing a multimodality imaging phantom for calibrating an imaging apparatus.
- the multimodality imaging phantom is for calibrating an imaging apparatus and comprises:
- a container having walls allowing a use of the imaging apparatus for imaging the interior thereof, the walls being provided with an inlet and an outlet;
- a first layer of tissue mimicking material located in a portion of the interior of the container
- At least one marker embedded in the first layer the at least one marker having an acoustic impedance that is 3 to 30 times higher than that of the first layer, an X-ray absorption coefficient that is 3 to 50 times higher than that of the first layer, and a MR axial relaxation time that is 2 to 20 times lower than that of the first layer;
- a second layer of tissue mimicking material located in a remaining portion of the interior, the second layer embedding a vessel operatively connected to the inlet and the outlet.
- the process provided by the present invention is for manufacturing a multimodality imaging phantom for calibrating an imaging apparatus, and comprises the steps of:
- FIG. 1 is a perspective view of a multimodality imaging phantom according to the invention.
- FIG. 2 is a exploded perspective view of parts of a phantom according to the invention.
- FIG. 3 is a top view of a phantom according to the invention.
- FIG. 4 is a cross-sectional view taken along line IV-IV of the phantom shown in FIG. 3.
- FIG. 5 is a top view of a first template used in a preferred embodiment of the process according to the invention.
- FIG. 6 is a bottom view of the first template illustrated in FIG. 5.
- FIG. 7 is a bottom view of a second template used in a preferred embodiment of the process according to the invention.
- FIG. 8 is a top view of the second template illustrated in FIG. 7.
- FIG. 9 is a top view of a two-part mold for preparing five pieces simulating vessels with different stenoses.
- FIG. 10 is a simulating piece prepared by using the mold illustrated in FIG. 9.
- FIG. 11 is a perspective view of a phantom according to another embodiment of the invention, with simulating pieces mounted therein.
- FIG. 12 is a photograph of a top view of a phantom according to the invention taken with a digital subtraction X-ray angiography apparatus at zero cranio-caudal or lateral angulation.
- FIG. 13 is a photograph of a perspective view of a portion of the phantom of FIG. 12 taken with a B-mode ultrasound apparatus.
- FIG. 14 is an image of a cross-sectional view of the phantom of FIG. 12 taken with a X-ray computerized tomography scanner.
- FIG. 15 is a photograph of a top cross-sectional view of the phantom of FIG. 12 taken with a magnetic resonance imaging apparatus.
- the present invention is directed to a multimodality imaging phantom for calibrating an imaging apparatus, and more preferably, the apparatus uses one of the following imaging modalities: ultrasonography, X-ray angiography, X-ray computed tomography and magnetic resonance imaging.
- the multimodality imaging phantom ( 1 ) comprises a container ( 10 ) having walls ( 12 ) allowing a use of the imaging apparatus (not shown) for imaging the interior ( 14 ) thereof.
- the walls ( 12 ) are provided with an inlet ( 16 ) and an outlet ( 18 ).
- the phantom ( 1 ) also comprises a first layer ( 20 ) of tissue mimicking material located in a portion of the interior ( 14 ) of the container ( 10 ). At least one marker ( 22 ) is embedded in the first layer ( 20 ).
- the markers ( 22 ) have an acoustic impedance that is 3 to 30 times higher than that of the first layer ( 20 ), an X-ray absorption coefficient that is 3 to 50 times higher than that of the first layer ( 20 ), and a MR (magnetic resonance) axial relaxation time that is 2 to 20 times lower than that of the first layer ( 20 ).
- the markers ( 22 ) have an acoustic impedance that is 10 to 15 times higher than that of the first layer ( 20 ), an X-ray absorption coefficient that is 10 to 20 times higher than that of the first layer ( 20 ), and/or a MR axial relaxation time that is 4 to 7 times lower than that of the first layer ( 20 ).
- the MR axial relaxation time is a longitudinal relaxation time T 1 .
- the phantom further comprises a second layer ( 24 ) of tissue mimicking material located in a remaining portion of the interior ( 14 ) of the container ( 10 ).
- a vessel ( 26 ) is embedded in the second layer ( 24 ) and is operatively connected to the inlet ( 16 ) and the outlet ( 18 ).
- the inlet ( 16 ) and the outlet ( 18 ) are used for connecting the vessel ( 26 ) to external devices (not shown) such as a pump to generate fluid circulation inside the vessel ( 26 ).
- the circulation of the fluid in the vessel ( 26 ) advantageously mimics the blood circulation.
- the fluid can also be static in the vessel ( 26 ).
- the phantom ( 1 ) can comprise more than one vessel and consequently more than one set of inlet ( 16 ) and outlet ( 18 ) as illustrated on FIG. 11.
- the vessel ( 26 ) can also be a bifurcation connected to an inlet ( 16 ) and to outlets ( 18 ), and the phantom ( 1 ) can comprises one or more bifurcations.
- the inlets ( 16 ) of the sets are located on a same side of the container ( 10 ). It should be understood that the inlets ( 16 ) and outlets ( 18 ) can be mounted so as to produce a liquid circulation in the vessels ( 26 ) in opposite directions if desired.
- the multimodality imaging phantom is particularly useful for calibrating devices for imaging vascular conduits.
- the phantom is compatible with X-ray, ultrasound and magnetic resonance imaging techniques. It allows testing, calibration, and inter-modality comparative studies of imaging devices, in static or dynamic flow conditions. It also provides a geometric reference for evaluation of accuracy of imaging devices.
- a vessel ( 26 ) of known desired geometry runs throughout the second layer ( 24 ) and is connected to an inlet ( 16 ) and outlet ( 18 ) at its extremities for generating a flow circulation in the vessel ( 26 ).
- the phantom also contains at least one fiducial marker ( 22 ) detectable in the modalities: X-ray, ultrasound and magnetic resonance.
- the markers ( 22 ) are implanted at precise known locations to allow identification and orientation of plane views, and it can be used for calibration, resealing and fusion of 3D images obtained from different modalities, and 3D image reconstruction from angiographic plane views.
- Composition of the first and the second layers ( 20 and 24 ) as well as the markers ( 22 ), are selected so that they meet two major requirements: firstly, materials used to manufacture the first and the second layers ( 20 and 24 ) should create no or a minimum of artifacts on images in any modality, and secondly, the marker ( 22 ) should be easily detected and identified on images obtained from all the modalities, so that they can be properly used for 3D reconstruction or multimodality image fusion.
- the markers ( 22 ) appear clearly on phantom images when there is high contrast between them and the material in which they are inserted, i.e. the first layer ( 20 ). This means that the markers ( 22 ) must have different characteristics than those of the material of the first layer ( 20 ).
- Tissue-mimicking material of the first layer ( 20 ) and the markers ( 22 ) are chosen so as to provide such contrast in all the modalities for which the phantom is designed to be used.
- the use of solid markers is preferred since it prevents the risk of diffusion into the surrounding material of the first layer ( 20 ), which can happen when using a liquid marker consisting in a fluid (for example MRA contrast agents such as gadolinium, X-ray contrast agent such as iodine and ultrasound contrast agent such as encapsulated gas bubbles) introduced in sealed cavities into the material of the first layer ( 20 ).
- MRA contrast agents such as gadolinium, X-ray contrast agent such as iodine and ultrasound contrast agent such as encapsulated gas bubbles
- markers ( 22 ) made of glass and a tissue mimicking material of the first layer ( 20 ) containing at least one fat component.
- the at least one fat component is preferably an oil which is advantageously a paraffinic oil.
- the tissue mimicking material of the first layer ( 20 ) is a gel of agar containing a paraffinic oil
- the tissue mimicking material of the second layer ( 24 ) is a gel of agar.
- the preferred composition of the first and second layers ( 20 , 24 ) is given in details below.
- acoustic imaging In acoustic imaging (ultrasonography), contrast between two adjacent materials results from a difference of acoustic impedance.
- Agar gels are known to have an acoustic impedance of about 1.5 ⁇ 10 5 g/cm ⁇ 2 s ⁇ 1 .
- the acoustic impedance is in the range of 1.5 to 1.8 ⁇ 10 5 g/cm ⁇ 2 s ⁇ 1 . Therefore, as far as acoustic imaging is concerned, fiducial markers ( 22 ) could be made of any material having a much greater impedance, for them to be clearly seen, for example ten times.
- the material of the fiducial markers ( 22 ) should not have a too high mismatch in acoustic impedance to avoid exaggerated attenuation and shadowing behind the markers.
- glass balls which have an impedance of 14.5 ⁇ 10 5 g/cm ⁇ 2 s ⁇ 1 , are used as markers ( 22 ). They appear as white bright circles on B-mode ultrasound images as shown in FIG. 13.
- contrast is essentially based on the difference of relaxation times.
- the relaxation times comprise the longitudinal relaxation time T 1 and transverse relaxation time T 2 .
- Medical images are usually T 1 -weighted, i.e. that the contrast between two tissues results from the difference between their respective values of T 1 .
- materials with low longitudinal relaxation time appear as bright on T 1 -weighted images.
- metallic markers could not be used because they create artifacts which prevent from precise determination of the center of the markers on images.
- Small glass balls are preferred since they are compatible with MRA in addition of being a good selection for ultrasound and X-ray.
- fat components are known to have low values of T 1 which range from about 200 to about 500 ms, and provide a high contrast on MRA. Therefore, oil has been added into the agar-based gel layer ( 20 ) in which markers ( 22 ) are inserted. The signal level of the oil-agar gel mixture is then much higher, and the fiducial glass markers ( 22 ) thus appear as black circles, hypo-signal, on a light-gray background, as it can be seen in FIG. 15.
- the container ( 10 ) of the phantom is preferably made of polyethylen and the interior ( 14 ) has a semi-cylindrical shape.
- the diameter of the semi-cylindrical cavity is 4 inches (101.6 mm) and its length is 9 inches (228.6 mm).
- the first layer ( 20 ) is preferably molded in the container ( 10 ) so as to have a semi-cylindrical shape of controlled thickness as detailed herein below.
- the remaining portion of the container ( 10 ) is filled with an agar-based gel (the second layer 24 ) with a semi-cylindrical shape at the bottom superimposed on the first layer ( 20 ) of the agar-oil mixture.
- markers ( 22 ) of known diameter are implanted at precise known positions and depths in the first layer ( 20 ) before the application of the second layer ( 24 ).
- the markers ( 22 ) are to be used as fiducial geometrical markers for the purpose of calibrating medical imaging apparatuses, but also in reconstruction of 3D images from plane angiographic views. They also provide a tool for aligning, resizing and fusing the images obtained from the different modalities. More preferably, twenty-five markers ( 22 ) are inserted at non-symmetrical positions as shown in FIG. 3.
- Each marker ( 22 ) is a glass ball of 3 mm in diameter and is implanted at a controlled angular position and depth, 6 mm as a preference, from the upper surface of the first layer ( 20 ) as illustrated in FIG. 4.
- the twenty-five markers ( 22 ) are divided in five sets of five markers ( 22 ) each, see FIG. 3.
- the five markers ( 22 ) are contained in cross-sectional and longitudinal planes of the container ( 10 ).
- One set is placed in the central axis, and the two sets on both sides are placed at non-symmetrical distances so as to facilitate the determination of the phantom orientation on medical images, especially on angiographic images.
- the markers ( 22 ) are implanted at non-symmetrical positions on either side of the symmetry axis.
- Said fiducial markers ( 22 ) have two functions. Firstly, as they are implanted at precise known locations in the phantom (1) and have a known diameter, they provide a calibration tool for the evaluation of image deformation or distortion inherent to the imaging apparatuses. They can also be used in 3D reconstruction techniques from plane angiographic images, as a basis for the calculation of the parameters of the planar projection associated to each view. Secondly, the markers ( 22 ) have been positioned in the phantom ( 1 ) so that they can be individually identified on images acquired by any modality.
- markers ( 22 ) Because different axial and radial distances were selected to position the markers ( 22 ), this can be achieved by measuring the distance between markers ( 22 ) in the neighborhood. They thus provide a way of aligning images obtained from different modalities, which is necessary for correct comparison, resizing and fusion of said images.
- the vessel ( 26 ) is made by a lost-material casting technique.
- the lost-material casting technique uses a low melting point metallic alloy being preferably a cerollow alloy. Such technique is described herein below.
- the top of the container ( 10 ) is closed by a cover ( 28 ) consisting in a polyethylen sheet.
- the cover ( 28 ) is secured to the container ( 10 ) by means of a series of eight nylon screws ( 30 ) introduced in threaded holes ( 32 ) made in the lateral walls ( 12 ) of the container ( 10 ).
- Securing the cover ( 28 ) is performed in a water bath to prevent air bubbles from remaining between the second layer ( 24 ) and the cover ( 28 ). Further air ingression inside the phantom is prevented by a rubber gasket ( 34 ) installed between the cover ( 28 ) and the container ( 10 ) to assure a perfect seal.
- the phantom needs to be protected from air to avoid drying out of the agar-based gel and proliferation of microorganisms.
- the cover ( 28 ) allows to pressurize the fluid inside the vessel ( 26 ) and prevent the breaking of the second layer ( 24 ), more particularly when the second layer ( 24 ) is made of a gel of agar.
- the container ( 10 ) and the cover ( 28 ) of the phantom may be made of any material compatible with all imaging techniques.
- they are made of polyethyen, which does not generate artifacts in any modality.
- the vessel ( 26 ) runs longitudinally all through the second layer ( 24 ) and is connected to the inlet ( 16 ) and outlet ( 18 ) which are preferably located at both extremities of the container ( 10 ).
- Each of the inlet ( 16 ) and the outlet ( 18 ) advantageously comprises a tubing ( 36 ) for connection to the vessel ( 26 ).
- Such tubing ( 36 ) is preferably a garolite tubing.
- Garolite is a material made of a continuous-woven glass fabric laminated with an epoxy resin.
- the inlet ( 16 ) and outlet ( 18 ) are preferably located at the extremities of the phantom, outside the region of interest for imaging.
- the tubing ( 36 ) is inserted in polypropylene bulkhead unions ( 38 ) screwed in the walls ( 12 ) of the container ( 10 ) and are secured by bolting the lock-nuts ( 40 ) of the bulkhead unions ( 38 ).
- the inlet ( 16 ) and outlet ( 18 ) provide a means for connecting the phantom to external devices (not shown) such as a pump to circulate blood mimicking fluid inside the vessel ( 26 ), and to use contrast agents when required for a good quality imaging.
- a thin impermeable material is provided at the external surface of the vessel ( 26 ) as a wall between the second layer ( 24 ) and the fluid.
- Such thin impermeable layer is preferably made of latex layer. Connections with devices generating fluid circulation can also be used to study physiological flow conditions inside the phantom.
- the tubing ( 36 ) of the inlet ( 16 ) and outlet ( 18 ) have the same inner diameter as that of the vessel ( 26 ), thus ensuring a smooth geometric transition between the lumen of the vessel ( 26 ) and the tubing ( 36 ). This has the advantage of minimizing perturbations of the flow that would result from any tubing diameter mismatch.
- the phantom ( 1 ) is preferably provided with a removable basin ( 42 ) on top thereof.
- the basin ( 42 ) has sides which are preferably formed by a rectangular-shaped wall ( 44 ) made in one piece of plexiglass.
- the wall ( 44 ) is sit on a rectangular rubber seal ( 46 ) and press down against the cover ( 28 ) so as to squeeze the rubber seal ( 46 ) by means of two bars ( 48 ) leaning on the wall ( 44 ) and being screwed in the container ( 10 ) by a screw ( 50 ) at each opposite end thereof.
- the bottom of the basin ( 42 ) is embodied by the cover ( 28 ).
- Water is poured in the basin ( 42 ) and the extremity of an ultrasonic probe (not shown) of the apparatus using ultrasonography is immersed in the water for imaging.
- the water can be replaced by an acoustic gel.
- the basin ( 42 ) is used only for ultrasound imaging and is removed when the phantom ( 1 ) is imaged in any other modality.
- the tissue-mimicking material of the second layer ( 24 ) is a gel of agar.
- agar gel is composed of 3 weight percent of agar, 8 weight percent of glycerol, 3 weight percent of cellulose particles, and 86 weight percent of degassed water.
- Glycerol is added to the mixture to increase the acoustic velocity of the gel, so that it is close to the value in living tissues being of 1540 m/s.
- the cellulose particles which are preferably the ones bought under the trademark SigmacellTM of Sigma Chemical, are added as an ultrasound scattering agent to provide better contrast between the vessel ( 26 ) and the second layer ( 24 ) in B-mode ultrasonic imaging.
- agar, glycerol and water are mixed together.
- the resulting mixture is stirred and heated until the agar powder is completely dissolved and a clear gelling liquid is obtained.
- cellulose is added, the mixture is stirred again, and cooled down to the proper temperature for pouring into the container ( 10 ) of the phantom ( 1 ), i.e. 45° C.
- the tissue-mimicking material of the first layer ( 20 ) is a gel of agar containing a paraffinic oil which is prepared as follow. Firstly, a volume V of a gel of agar/water/glycerol in the same proportions as for the tissue-mimicking material of the second layer ( 24 ) described above, is prepared. Then a volume ranging between V/2 and V of paraffinic oil is added. The mixture is heated and energetically stirred until the gel-oil emulsion becomes stable, i.e. water and oil do not separate after stirring. No cellulose particle is added.
- the proportion of oil included in the preparation of the gel is preferably selected in the range 33-50% in volume.
- agar-paraffinic oil mixture of the material of the first layer ( 20 ) and glass were found to be a suitable set of materials for fulfill the imaging conditions described above i.e. differences of acoustic impedance, X-ray absorption coefficient and MR axial relaxation time. Any other materials and especially other oils or fat components, and other kinds of glass, meeting such imaging conditions, may be suitable for the present invention.
- the present invention is also directed to a process for manufacturing a multimodality imaging phantom for calibrating an imaging apparatus.
- Such process comprises the following steps (a) to (e).
- Step (a) is providing a container ( 10 ) having walls ( 12 ) allowing a use of the imaging apparatus (not shown) for imaging the interior ( 14 ) thereof.
- the walls ( 12 ) are provided with at least one set of inlet ( 16 ) and outlet ( 18 ) as described above.
- Step (b) is providing a first layer ( 20 ) containing a first tissue mimicking material in a portion of the interior ( 14 ) of the container ( 10 ).
- Step (c) is embedding at least one marker ( 22 ) in the first layer ( 20 ) where the at least one marker ( 22 ) has an acoustic impedance that is 3 to 30 times higher than that of the first layer ( 20 ), an X-ray absorption coefficient that is 3 to 50 times higher than that of the first layer ( 20 ), and a MR axial relaxation time that is 2 to 20 times lower than that of the first layer ( 20 ).
- Step (d) is providing a second layer ( 24 ) containing a second tissue mimicking material in the remaining portion of the interior ( 14 ) of the container ( 10 ).
- Step (e) is embedding a vessel ( 26 ) in the second layer ( 24 ).
- the vessel ( 26 ) is operatively connected to the inlet ( 16 ) and the outlet ( 18 ) of the container ( 10 ).
- the steps (d) and (e) preferably comprise the following sub-steps (i) to (vi).
- Sub-step (i) is molding a simulating piece ( 52 ).
- two simulating pieces ( 52 ) are installed in the phantom ( 1 ) and the second layer ( 24 ) is not provided yet.
- the simulating piece ( 52 ) has an exterior shape simulating the vessel ( 26 ) to be formed.
- the simulating piece ( 52 ) is made of a molding material having a melting point lower than the melting point of the second tissue mimicking material.
- the molding material is a cerollow alloy which is preferably a cerro-indium alloy having the trademark Cerrolow 136TM sold by Cerrometal Products, Bellefonte, Pa., USA and having a melting point of 58° C.
- the simulating piece ( 52 ) is prepared by pouring the molding material in a liquid state in the aluminium mold ( 54 ) shown in FIG. 9.
- the mold ( 54 ) is made of two parts ( 56 and 58 ) that fit over each other.
- the interior face ( 57 and 59 ) of each part ( 56 and 58 ) of the mold ( 54 ) is shown in FIG. 9 as well as the half of five cavities ( 60 ) for pouring the molding material and forming five simulating pieces ( 52 ).
- the cerollow alloy which is the preferred molding material, is cooled at room temperature for two hours. It is then extracted from the mold ( 54 ) and hand-polished to remove surface irregularities as illustrated in FIG. 10.
- simulating pieces ( 52 ) with different stenoses ( 62 ) can be prepared. It should be understood that it is possible to prepare a simulating piece ( 52 ) of known controlled geometry that simulates any vascular pathologies with no axis of symmetry. For example, one of the simulating pieces ( 52 ) shown in the phantom ( 1 ) illustrated in FIG. 11 has only one stenosis ( 62 ).
- Sub-step (ii) is coating the simulating piece with a latex layer.
- the stimulating piece ( 52 ) is previously coated with a thin impermeable material, being preferably a latex layer, at the end of sub-step (i).
- the latex layer forms the wall of the vessel ( 26 ) which stays intact after removal of the moten cerollow alloy. This latex layer prevents diffusion into the second layer ( 24 ) of a contrast agent used in the fluid.
- Sub-step (iii) is connecting one end ( 51 ) of the simulating piece ( 52 ) to the inlet ( 16 ) of the container ( 10 ) and another end ( 53 ) of the simulating piece ( 52 ) to the outlet ( 18 ) of the container ( 10 ).
- Sub-step (iv) is pouring the second tissue mimicking material, while in a liquid state, in the remaining portion of the interior ( 14 ) of the container ( 10 ) so as to form the second layer ( 24 ) and embed the simulating piece ( 52 ).
- FIG. 11 represents the state of a phantom ( 1 ) just before executing sub-step (iv).
- Sub-step (v) is lowering the temperature of the second tissue mimicking material under its melting point so that the second tissue mimicking material becomes solid.
- Sub-step (vi) is melting and removing the simulating piece ( 52 ) by heating said simulating piece ( 52 ) at a temperature higher than the melting point of the molding material and lower than the melting point of the second tissue mimicking material.
- the simulating piece ( 52 ) is made of a cerollow alloy and the second tissue mimicking material is made of a gel of agar.
- removing the simulating piece by heating is advantageously performed as follow.
- the phantom ( 1 ) is heated in a water bath for several hours.
- the phantom ( 1 ) is installed in the water bath so that the inlet ( 16 ) and outlet ( 18 ) are vertically positioned and not in contact with the bottom of the bath that is kept at 65° C.
- the cerollow alloy starts melting out of the phantom ( 1 ) via the inlet ( 16 ) or the outlet ( 18 ) depending which one is underneath. Removal of the molten cerollow alloy creates in the gel an empty conduit having the shape of the initial simulating piece ( 26 ). Such conduit is called the vessel ( 26 ). Small residual cerollow particles can be removed by injection of water at 65° C. in the vessel ( 26 ) with a syringe.
- Sub-steps (i) to (vi) are a description of the lost-material casting technique for manufacturing a vessel ( 26 ).
- Other techniques to provide a vessel ( 26 ) can be used as any one known in the art. Even a real blood vessel can be used.
- steps (b) and (c) preferably comprise the following sub-steps (vii) to (xvi).
- Sub-step (vii) is pouring an amount of the first tissue mimicking material, while in a liquid state, in the portion of the interior ( 14 ) of the container ( 10 ) mentioned in step (b).
- the first tissue mimicking material has a melting point.
- the amount of the first tissue mimicking material that is poured represents between 70% to 90% of the total amount forming the first layer ( 20 ).
- Sub-step (viii) is placing a first template ( 64 ) on the amount of the first tissue mimicking material.
- the top surface ( 66 ) and the bottom surface ( 68 ) of the first template ( 64 ) are illustrated in FIGS. 5 and 6 respectively.
- the bottom surface ( 68 ) of the first template ( 64 ) has a semi-cylindrical shape.
- the shape of the first template ( 64 ) is designed to follow the interior ( 14 ) of the container ( 10 ) so that the first tissue mimicking material forms a layer of equal thickness, when solidified.
- the first template ( 64 ) has at least one pin ( 70 ) removably fixed thereto and extending in the first tissue mimicking material. In the preferred embodiment shown in FIG. 6, twenty-five pins ( 70 ) extend form the bottom surface ( 68 ) of the first template ( 64 ).
- the pin ( 70 ) is advantageously a screw and the head screw ( 72 ) is shown on the top surface ( 66 ) illustrated in FIG. 5.
- Sub-step (ix) is lowering the temperature of the first tissue mimicking material under its melting point so that the first tissue mimicking material becomes solid.
- Sub-step (x) is removing the at least one pin ( 70 ) so as to free at least one recess (not shown) in the solid first tissue mimicking material.
- the pin ( 70 ) which is a screw
- removing the pin ( 70 ) consists in screw off the pin ( 70 ).
- Sub-step (xi) is placing the at least one marker ( 22 ) in the at least one recess respectively.
- the recess has the same shape than the marker ( 22 ).
- the marker ( 22 ) is a ball of 3 mm of diameter
- the recess has a depth of 6 mm, a circular periphery, a width of 3 mm and a round bottom for snugly fitting the marker ( 22 ).
- Sub-step (xii) is removing the first template ( 64 ).
- Sub-step (xiii) is pouring another amount of the first tissue mimicking material, while in a liquid state.
- Sub-step (xiv) is placing a second template ( 74 ) on the first tissue mimicking material poured in sub-step (viii) so that the another amount of the first tissue mimicking material covers the at least one marker ( 22 ) and fills remaining portion of the at least one recess so as to surround completely the at least one marker ( 22 ).
- the bottom surface ( 76 ) and the top surface ( 78 ) of the second template ( 74 ) are illustrated in FIGS. 7 and 8 respectively. As it can be seen from FIG.
- the bottom surface ( 76 ) has a semi-cylindrical shape which is designed to follow the top surface of the solidified amount of first tissue mimicking material and therefore providing a first layer ( 20 ) of equal thickness.
- Two alignment pins ( 75 ) on the second template ( 74 ) (shown in FIG. 7) and corresponding holes ( 11 ) in the container ( 10 ) (shown in FIG. 3) ensure a correct positioning of the second template ( 74 ) onto the container ( 10 ).
- Sub-step (xv) is lowering the temperature of the first tissue mimicking material poured in step (xiii) under its melting point so that it becomes solid. After solidification, the two amounts of the first tissue mimicking material cannot be distinguished from one another, both visually and on the acquired images obtained from apparatuses of all modalities.
- Sub-step (xvi) is removing the second template ( 74 ). Then, the second layer ( 24 ) is provided as described above in step (d).
- the second tissue mimicking material is a gel of agar and the molding material of the simulating piece ( 52 ) is a Cerrolow 136TM
- the gel of agar is poured at 45° C. This temperature was found to be a good compromise because it is high enough to allow pouring before solidifying, and it is sufficiently low, compared with the melting point of Cerrolow 136TM, to avoid softening and deformation of the simulating piece.
- the gel of agar is then allowed to solidify at room temperature for approximately 10 hours.
Landscapes
- Health & Medical Sciences (AREA)
- Physics & Mathematics (AREA)
- Life Sciences & Earth Sciences (AREA)
- Engineering & Computer Science (AREA)
- Medical Informatics (AREA)
- Radiology & Medical Imaging (AREA)
- General Physics & Mathematics (AREA)
- General Health & Medical Sciences (AREA)
- Nuclear Medicine, Radiotherapy & Molecular Imaging (AREA)
- Biophysics (AREA)
- Pathology (AREA)
- Biomedical Technology (AREA)
- Heart & Thoracic Surgery (AREA)
- Molecular Biology (AREA)
- Surgery (AREA)
- Animal Behavior & Ethology (AREA)
- High Energy & Nuclear Physics (AREA)
- Public Health (AREA)
- Veterinary Medicine (AREA)
- Optics & Photonics (AREA)
- Condensed Matter Physics & Semiconductors (AREA)
- Chemical & Material Sciences (AREA)
- Medicinal Chemistry (AREA)
- Algebra (AREA)
- Computational Mathematics (AREA)
- Mathematical Analysis (AREA)
- Mathematical Optimization (AREA)
- Mathematical Physics (AREA)
- Pure & Applied Mathematics (AREA)
- Business, Economics & Management (AREA)
- Educational Administration (AREA)
- Educational Technology (AREA)
- Theoretical Computer Science (AREA)
- Apparatus For Radiation Diagnosis (AREA)
- Magnetic Resonance Imaging Apparatus (AREA)
Abstract
Description
- The present invention relates to a multimodality imaging phantom and a process for manufacturing the same. The multimodality imaging phantom is particularly useful for calibrating imaging devices or apparatuses using different imaging modalities.
- Several medical imaging techniques are now currently in use to investigate the severity of vascular diseases (i.e. quantification of the vascular lumen geometry) and enable clinicians to detect stenoses, thromboses, development of collateral vessels, aneurysms, or malformations. The techniques are based either on X-rays (X-ray angiography, and computerized tomography (CT)), ultrasonography (B-mode, M-mode, pulsed-wave Doppler, power Doppler, color Doppler, intravascular ultrasound (IVUS)), or on magnetic resonance angiography (MRA) (gradient-recalled echo sequence, phase-contrast, gadolinium enhanced angiography). Angiography (MRA) provides geometrical data on the vessel lumen, whereas IVUS and CT can be used independently or complementary to angiography to investigate the arterial wall morphology and composition. Knowledge on the hemodynamics is also of great interest to evaluate the consequences of lesions on blood supply to the tissues perfused by diseased vessels. Doppler ultrasound and phase contrast MRA allow to study blood flow, namely to measure blood velocities in the vessels. As the precise quantification of morphological and hemodynamic parameters is the basis of the clinical diagnosis, calibration of the medical imaging apparatuses is an essential step required for accurate imaging and evaluation of blood vessels. Test objects, known as calibration phantoms, are commonly used for this purpose and specific phantoms have been developed to meet the requirements associated to each imaging modality.
- Even after calibration, no imaging technique is error free. In the literature, plane X-ray angiography is considered as the gold standard (Bendib K., Poirier C., Croisille P., Roux J. P., Revel D., and Amiel M.—Caractérisation d'une sténose arterielle par imagerie 3D, Journal de Radiologie, 1999, 80:1561-1567) for the evaluation of arterial diseases, because it is the technique with the best spatial resolution. Nevertheless, other techniques, especially those allowing 3D imaging, bring important additional information concerning the morphology, the severity, and the location of the lesion. This is why comparative studies of imaging techniques, in the same experimental conditions, are necessary to assess the accuracy and determine the advantages and limitations of each one. Moreover, a gold standard, different from the tested techniques, should be available for precise assessment.
- Vascular flow phantoms are ideal tools for such studies since they provide a way of testing the geometric accuracy, with easy reproducibility of the experimental conditions when different modalities are tested. They can also be used to compare the blood flow velocity patterns obtained by ultrasound and MRA. Moreover, it is possible to reproduce vascular pathologies, with a known geometry that can be accurately determined during fabrication, and which can be used as the “gold standard reference” for evaluation of imaging devices. Multimodality phantoms have to meet three major requirements. First, they must be compatible with many if not all the imaging modalities evaluated, i.e. it is necessary that the vessel position can be clearly identified on the images, with no or minimum artifacts in any modality. Second, they should be anthropomorphic, i.e. their geometry should mimic as close as possible the complexity of real human vessels. Finally, they should contain markers visible in all modalities for image calibration, resealing and fusion.
- Multimodality anthropomorphic vascular flow phantoms have been proposed in the recent years using three major techniques: stereolithography, phantoms including real vessels and lost-material casting method. For instance, Creasy et al. (Creasy J. L., Crump D. B., Knox K., Kerber C. W., and Price R. R.—Design and Evaluation of a Flow Phantom, Academic radiology, 1995, 2:902-904) presented a simple cranial blood flow phantom compatible with X-ray, MRA and CT angiography. It consisted in an acrylic skull filled with a silicone polymer mimicking human brain tissue, which contains the main cerebral vessels. Arteries were modeled from actual human arteries by injecting fresh cadaver arteries with acrylic resin. Veins were constructed in wax using resin cast human model duplicating dimensions and shape of actual cerebral human veins. When the vein and artery models were placed and the skull filled with silicon polymer, wax was removed thermically and chemically. Fahrig et al. (Fahrig R., Nikolov H., Fox A. J., and Holdsworth D. W.—A Three-Dimensional Cerebrovascular Flow Phantom, Medical Physics, 1999, 26(8):1589-1599) constructed a three-dimensional cerebrovascular flow phantom compatible with X-ray angiography, MRA and CT techniques using data taken from the literature and a casting method similar to that described above and cerrolow 117 as the casting material. The authors tested the phantom for geometric accuracy using high resolution MRA and CT protocols. Their results showed good agreement (within 4%) between the arterial diameters determined from the radiographic images and those measured on cerrolow cores before their implantation.
- To solve the problem of realistic anthropomorphic geometry, including diseased segments, studies have been made on phantoms derived from real vessels harvested on cadavers (Kerber C. W., and Heilman C. B.—Flow Dynamics in the Human Carotid Artery: I. Preliminary Observations Using a Transparent Elastic Model, American Journal of Neuroradiology, 1992, 13:173-180). Dabrowski et al. (Dabrowski W., Dunmore-Buyze J., Rankin R. N., Holdsworth D. W., and Fenster A.—A real vessel phantom for imaging experimentation, Medical Physics, 1997, 24(5):687-693) used a human abdominal aorta, fixed with a 10% formaldehyde solution at 90 mmHg to preserve its geometry, to perform comparisons of X-ray angiography, CT scan and 3D B-mode ultrasound. The images obtained from the three modalities could be compared with each other and showed good overall correlation. These real vessel phantoms had two limitations: first, the geometry of the artery was not known a priori, and thus, there was no gold standard to assess the accuracy of the imaging devices. Second, the geometry of each artery was unique and could not be duplicated if the vessel was damaged.
- Frayne et al. (Frayne R., Gowman L. M., Rickey D. W., Holdsworth D. W., Picot P. A., Drangova M., Chu K. C., Caldwell C. B., Fenster A., and Rutt B. K.—A Geometrically Accurate Vascular Phantom for Comparative Studies of X-Ray, Ultrasound, and Magnetic Resonance Vascular Imaging: Construction and Geometrical Verification, Medical Physics, 1993, 20(2):415-425) built a flow phantom of the human carotid bifurcation based on geometrical data taken from the literature by using a thin-walled polyester-resin replica of the carotid bifurcation surrounded by an agar tissue-mimicking material (lost-material casting technique). The two-parts mold was machined in blocks of acrylic using a numerical milling machine and the casting material was wax. The blood- and tissue-mimicking materials had X-ray, ultrasound and MRA properties close to those of blood and human tissues, but polyester resin was found to be a poor ultrasound and MRA tissue-mimicking material. Static images were recorded with X-ray angiography, CT, ultrasound and MRA for evaluation of the geometric accuracy of these techniques. Velocity images were acquired under steady flow with color Doppler and phase contrast MRA. The two techniques gave flow patterns which qualitatively agreed with each other and with literature data, and measured volume flow-rates were in good agreement (4.4%) with actual values.
- Smith et al. (Smith R. F., Frayne R., Moreau M., Rutt B. K., Fenster A., and Holdsworth D. W.—Stenosed Anthropomorphic Vascular Phantoms for Digital Substraction Angiography, Magnetic Resonance and Doppler Ultrasound Investigations, SPIE Physics of medical imaging, 1994, 2163:235-242) improved the method proposed by Frayne et al (1993) by using aluminum molds, replacing wax with cerrobend 158 and agar gel with a polyester resin. A drawback of this method is the absence of tissue-mimicking material around the vessel, which has implications in MRA and ultrasound images. Recently, Bendib et al (1999) used vascular phantoms to compare the accuracy of MRA, CT angiography and 3D X-ray digital substraction angiography for evaluation of stenoses using stereolithography. One limitation of stereolithography is that it only allows fabrication of rigid-wall phantoms, and the type of materials that can be used is limited. Moreover, the lumen of the vessel is not perfectly smooth (Fahrig et al., 1999). The phantoms were filled with contrast agents compatible with each imaging modality, but there was no fluid circulation. The authors found that among the three methods tested, 3D X-ray angiography was more accurate than MRA and CT for the evaluation of the degree, the shape and the location of stenoses.
- Also known in the art, there are the following U.S. Pat. Nos. 4,331,021; 4,499,375; 4,551,678; 4,644,276; 4,724,110; 4,794,631; 4,843,866; 4,985,906; 5,312,755; 5,560,242; and 5,793,835.
- However, all of these patents describe apparatus and methods that are each limited to a single mode of imaging.
- There is a need for a phantom using different modes of imaging like X-ray, ultrasound and magnetic resonance (MR) to calibrate apparatuses
- An object of the invention is to provide a multimodality imaging phantom for calibrating an imaging apparatus.
- Another object of the invention is to provide a process for manufacturing a multimodality imaging phantom for calibrating an imaging apparatus.
- The multimodality imaging phantom provided by the present invention is for calibrating an imaging apparatus and comprises:
- a container having walls allowing a use of the imaging apparatus for imaging the interior thereof, the walls being provided with an inlet and an outlet;
- a first layer of tissue mimicking material located in a portion of the interior of the container;
- at least one marker embedded in the first layer, the at least one marker having an acoustic impedance that is 3 to 30 times higher than that of the first layer, an X-ray absorption coefficient that is 3 to 50 times higher than that of the first layer, and a MR axial relaxation time that is 2 to 20 times lower than that of the first layer; and
- a second layer of tissue mimicking material located in a remaining portion of the interior, the second layer embedding a vessel operatively connected to the inlet and the outlet.
- The process provided by the present invention is for manufacturing a multimodality imaging phantom for calibrating an imaging apparatus, and comprises the steps of:
- a) providing a container having walls allowing a use of the imaging apparatus for imaging the interior thereof, the walls being provided with an inlet and an outlet;
- b) providing a first layer containing a first tissue mimicking material in a portion of the interior of the container;
- c) embedding at least one marker in the first layer, the at least one marker having an acoustic impedance that is 5 to 20 times higher than that of the first layer, an X-ray absorption coefficient that is 3 to 50 times higher than that of the first layer, and a MR axial relaxation time that is 2 to 10 times lower than that of the first layer;
- d) providing a second layer containing a second tissue mimicking material in the remaining portion of the interior of the container; and
- e) embedding a vessel in the second layer, the vessel being operatively connected to the inlet and the outlet of the container.
- The invention and its process of manufacture will be better understood upon reading the following non restrictive description of a preferred embodiment thereof, made with references to the accompanying drawings.
- FIG. 1 is a perspective view of a multimodality imaging phantom according to the invention.
- FIG. 2 is a exploded perspective view of parts of a phantom according to the invention.
- FIG. 3 is a top view of a phantom according to the invention.
- FIG. 4 is a cross-sectional view taken along line IV-IV of the phantom shown in FIG. 3.
- FIG. 5 is a top view of a first template used in a preferred embodiment of the process according to the invention.
- FIG. 6 is a bottom view of the first template illustrated in FIG. 5.
- FIG. 7 is a bottom view of a second template used in a preferred embodiment of the process according to the invention.
- FIG. 8 is a top view of the second template illustrated in FIG. 7.
- FIG. 9 is a top view of a two-part mold for preparing five pieces simulating vessels with different stenoses.
- FIG. 10 is a simulating piece prepared by using the mold illustrated in FIG. 9.
- FIG. 11 is a perspective view of a phantom according to another embodiment of the invention, with simulating pieces mounted therein.
- FIG. 12 is a photograph of a top view of a phantom according to the invention taken with a digital subtraction X-ray angiography apparatus at zero cranio-caudal or lateral angulation.
- FIG. 13 is a photograph of a perspective view of a portion of the phantom of FIG. 12 taken with a B-mode ultrasound apparatus.
- FIG. 14 is an image of a cross-sectional view of the phantom of FIG. 12 taken with a X-ray computerized tomography scanner.
- FIG. 15 is a photograph of a top cross-sectional view of the phantom of FIG. 12 taken with a magnetic resonance imaging apparatus.
- The present invention is directed to a multimodality imaging phantom for calibrating an imaging apparatus, and more preferably, the apparatus uses one of the following imaging modalities: ultrasonography, X-ray angiography, X-ray computed tomography and magnetic resonance imaging.
- As shown in FIGS. 1, 2,3, 4 and 11, the multimodality imaging phantom (1) comprises a container (10) having walls (12) allowing a use of the imaging apparatus (not shown) for imaging the interior (14) thereof. The walls (12) are provided with an inlet (16) and an outlet (18).
- As shown in FIG. 4, the phantom (1) also comprises a first layer (20) of tissue mimicking material located in a portion of the interior (14) of the container (10). At least one marker (22) is embedded in the first layer (20). The markers (22) have an acoustic impedance that is 3 to 30 times higher than that of the first layer (20), an X-ray absorption coefficient that is 3 to 50 times higher than that of the first layer (20), and a MR (magnetic resonance) axial relaxation time that is 2 to 20 times lower than that of the first layer (20). In accordance with a preferred embodiment of the invention, the markers (22) have an acoustic impedance that is 10 to 15 times higher than that of the first layer (20), an X-ray absorption coefficient that is 10 to 20 times higher than that of the first layer (20), and/or a MR axial relaxation time that is 4 to 7 times lower than that of the first layer (20). Preferably, the MR axial relaxation time is a longitudinal relaxation time T1.
- Referring more particularly to FIGS. 2 and 4, the phantom further comprises a second layer (24) of tissue mimicking material located in a remaining portion of the interior (14) of the container (10). A vessel (26) is embedded in the second layer (24) and is operatively connected to the inlet (16) and the outlet (18). The inlet (16) and the outlet (18) are used for connecting the vessel (26) to external devices (not shown) such as a pump to generate fluid circulation inside the vessel (26). The circulation of the fluid in the vessel (26) advantageously mimics the blood circulation. The fluid can also be static in the vessel (26). The phantom (1) can comprise more than one vessel and consequently more than one set of inlet (16) and outlet (18) as illustrated on FIG. 11. The vessel (26) can also be a bifurcation connected to an inlet (16) and to outlets (18), and the phantom (1) can comprises one or more bifurcations. In FIG. 11, the inlets (16) of the sets are located on a same side of the container (10). It should be understood that the inlets (16) and outlets (18) can be mounted so as to produce a liquid circulation in the vessels (26) in opposite directions if desired.
- The multimodality imaging phantom is particularly useful for calibrating devices for imaging vascular conduits. The phantom is compatible with X-ray, ultrasound and magnetic resonance imaging techniques. It allows testing, calibration, and inter-modality comparative studies of imaging devices, in static or dynamic flow conditions. It also provides a geometric reference for evaluation of accuracy of imaging devices. A vessel (26) of known desired geometry runs throughout the second layer (24) and is connected to an inlet (16) and outlet (18) at its extremities for generating a flow circulation in the vessel (26). The phantom also contains at least one fiducial marker (22) detectable in the modalities: X-ray, ultrasound and magnetic resonance. The markers (22) are implanted at precise known locations to allow identification and orientation of plane views, and it can be used for calibration, resealing and fusion of 3D images obtained from different modalities, and 3D image reconstruction from angiographic plane views.
- Composition of the first and the second layers (20 and 24) as well as the markers (22), are selected so that they meet two major requirements: firstly, materials used to manufacture the first and the second layers (20 and 24) should create no or a minimum of artifacts on images in any modality, and secondly, the marker (22) should be easily detected and identified on images obtained from all the modalities, so that they can be properly used for 3D reconstruction or multimodality image fusion. The markers (22) appear clearly on phantom images when there is high contrast between them and the material in which they are inserted, i.e. the first layer (20). This means that the markers (22) must have different characteristics than those of the material of the first layer (20). Tissue-mimicking material of the first layer (20) and the markers (22) are chosen so as to provide such contrast in all the modalities for which the phantom is designed to be used. The use of solid markers is preferred since it prevents the risk of diffusion into the surrounding material of the first layer (20), which can happen when using a liquid marker consisting in a fluid (for example MRA contrast agents such as gadolinium, X-ray contrast agent such as iodine and ultrasound contrast agent such as encapsulated gas bubbles) introduced in sealed cavities into the material of the first layer (20).
- To obtain the differential characteristics between the markers (22) and the first layer (20), it is preferred to use markers (22) made of glass and a tissue mimicking material of the first layer (20) containing at least one fat component. The at least one fat component is preferably an oil which is advantageously a paraffinic oil.
- According to a preferred embodiment of the invention, the tissue mimicking material of the first layer (20) is a gel of agar containing a paraffinic oil, and the tissue mimicking material of the second layer (24) is a gel of agar. The preferred composition of the first and second layers (20, 24) is given in details below.
- In acoustic imaging (ultrasonography), contrast between two adjacent materials results from a difference of acoustic impedance. Agar gels are known to have an acoustic impedance of about 1.5×105 g/cm−2s−1. For a mixture of agar gel with oil, the acoustic impedance is in the range of 1.5 to 1.8×105 g/cm−2s−1. Therefore, as far as acoustic imaging is concerned, fiducial markers (22) could be made of any material having a much greater impedance, for them to be clearly seen, for example ten times. On the other hand, the material of the fiducial markers (22) should not have a too high mismatch in acoustic impedance to avoid exaggerated attenuation and shadowing behind the markers. In a preferred embodiment of the invention, glass balls which have an impedance of 14.5×105 g/cm−2s−1, are used as markers (22). They appear as white bright circles on B-mode ultrasound images as shown in FIG. 13.
- For imaging techniques based on X-ray such as X-ray angiography and computerized tomography, contrast on the images will result from a difference in X-ray absorption of the different materials. The absorption coefficient of different kinds of glasses is ranging from 1 to 10 cm−1 and the one of a gel of agar with paraffinic oil is about 0.24 cm−1 at 90 kVp. Consequently, materials like glass, which have an absorption coefficient significantly higher than that of a gel of agar will appear clearly both in digital angiography and CT images, as can be seen on FIGS. 12 and 14, respectively. Distortion in the image of FIG. 12 is due to the imaging apparatus.
- For magnetic resonance imaging, contrast is essentially based on the difference of relaxation times. The relaxation times comprise the longitudinal relaxation time T1 and transverse relaxation time T2. Medical images are usually T1-weighted, i.e. that the contrast between two tissues results from the difference between their respective values of T1. As the recovered spin-echo signal is a decreasing function of T1, materials with low longitudinal relaxation time appear as bright on T1-weighted images. In the preferred embodiments of the invention, metallic markers could not be used because they create artifacts which prevent from precise determination of the center of the markers on images. Small glass balls are preferred since they are compatible with MRA in addition of being a good selection for ultrasound and X-ray. However, it is important to understand that the magnetic resonance signal level from the agar gel is low, and not very different from that of glass for which the relaxation time T1 is about 1000-1200 ms. Thus, glass markers can not easily be detected when inserted in agar gel alone. Based on the article of Bottomley et al. (Bottomley P.A., Foster T. H., Argersinger R. E., Pfeifer L. M.—A Review of Normal Tissue Hydrogen NMR Relaxation Times and Relaxation Mechanisms: Dependence on Tissue Type, NMR Frequency, Temperature, Species, Excision, and Age, Med. Phys. 1984,11:425-448), relating to adipose tissues on medical images, fat components are known to have low values of T1 which range from about 200 to about 500 ms, and provide a high contrast on MRA. Therefore, oil has been added into the agar-based gel layer (20) in which markers (22) are inserted. The signal level of the oil-agar gel mixture is then much higher, and the fiducial glass markers (22) thus appear as black circles, hypo-signal, on a light-gray background, as it can be seen in FIG. 15.
- Referring to FIGS. 2, 3 and4, the container (10) of the phantom is preferably made of polyethylen and the interior (14) has a semi-cylindrical shape. In the preferred embodiment illustrated in FIG. 2, the diameter of the semi-cylindrical cavity is 4 inches (101.6 mm) and its length is 9 inches (228.6 mm). The first layer (20) is preferably molded in the container (10) so as to have a semi-cylindrical shape of controlled thickness as detailed herein below. According to the preferred embodiment of the invention illustrated in FIG. 4, the remaining portion of the container (10) is filled with an agar-based gel (the second layer 24) with a semi-cylindrical shape at the bottom superimposed on the first layer (20) of the agar-oil mixture.
- Advantageously, several markers (22) of known diameter are implanted at precise known positions and depths in the first layer (20) before the application of the second layer (24). The markers (22) are to be used as fiducial geometrical markers for the purpose of calibrating medical imaging apparatuses, but also in reconstruction of 3D images from plane angiographic views. They also provide a tool for aligning, resizing and fusing the images obtained from the different modalities. More preferably, twenty-five markers (22) are inserted at non-symmetrical positions as shown in FIG. 3. Each marker (22) is a glass ball of 3 mm in diameter and is implanted at a controlled angular position and depth, 6 mm as a preference, from the upper surface of the first layer (20) as illustrated in FIG. 4. The twenty-five markers (22) are divided in five sets of five markers (22) each, see FIG. 3. For each set, the five markers (22) are contained in cross-sectional and longitudinal planes of the container (10). One set is placed in the central axis, and the two sets on both sides are placed at non-symmetrical distances so as to facilitate the determination of the phantom orientation on medical images, especially on angiographic images. For the same reason, in each cross-sectional planar set, the markers (22) are implanted at non-symmetrical positions on either side of the symmetry axis. Said fiducial markers (22) have two functions. Firstly, as they are implanted at precise known locations in the phantom (1) and have a known diameter, they provide a calibration tool for the evaluation of image deformation or distortion inherent to the imaging apparatuses. They can also be used in 3D reconstruction techniques from plane angiographic images, as a basis for the calculation of the parameters of the planar projection associated to each view. Secondly, the markers (22) have been positioned in the phantom (1) so that they can be individually identified on images acquired by any modality. Because different axial and radial distances were selected to position the markers (22), this can be achieved by measuring the distance between markers (22) in the neighborhood. They thus provide a way of aligning images obtained from different modalities, which is necessary for correct comparison, resizing and fusion of said images.
- According to a preferred embodiment of the invention, the vessel (26) is made by a lost-material casting technique. Advantageously, the lost-material casting technique uses a low melting point metallic alloy being preferably a cerollow alloy. Such technique is described herein below.
- Referring more particularly to FIG. 2, the top of the container (10) is closed by a cover (28) consisting in a polyethylen sheet. The cover (28) is secured to the container (10) by means of a series of eight nylon screws (30) introduced in threaded holes (32) made in the lateral walls (12) of the container (10). Securing the cover (28) is performed in a water bath to prevent air bubbles from remaining between the second layer (24) and the cover (28). Further air ingression inside the phantom is prevented by a rubber gasket (34) installed between the cover (28) and the container (10) to assure a perfect seal. The phantom needs to be protected from air to avoid drying out of the agar-based gel and proliferation of microorganisms. Moreover, the cover (28) allows to pressurize the fluid inside the vessel (26) and prevent the breaking of the second layer (24), more particularly when the second layer (24) is made of a gel of agar. It should be understand that the container (10) and the cover (28) of the phantom may be made of any material compatible with all imaging techniques. Advantageously, they are made of polyethyen, which does not generate artifacts in any modality.
- According to the preferred embodiment of the invention illustrated in FIG. 2, the vessel (26) runs longitudinally all through the second layer (24) and is connected to the inlet (16) and outlet (18) which are preferably located at both extremities of the container (10). Each of the inlet (16) and the outlet (18) advantageously comprises a tubing (36) for connection to the vessel (26). Such tubing (36) is preferably a garolite tubing. Garolite is a material made of a continuous-woven glass fabric laminated with an epoxy resin. Other nonporous and non-metallic materials such as glass or acrylic may be used, with no major imaging problem since the inlet (16) and outlet (18) are preferably located at the extremities of the phantom, outside the region of interest for imaging. The tubing (36) is inserted in polypropylene bulkhead unions (38) screwed in the walls (12) of the container (10) and are secured by bolting the lock-nuts (40) of the bulkhead unions (38). The inlet (16) and outlet (18) provide a means for connecting the phantom to external devices (not shown) such as a pump to circulate blood mimicking fluid inside the vessel (26), and to use contrast agents when required for a good quality imaging. To avoid possible diffusion of the contrast agent into the second layer (24), a thin impermeable material is provided at the external surface of the vessel (26) as a wall between the second layer (24) and the fluid. Such thin impermeable layer is preferably made of latex layer. Connections with devices generating fluid circulation can also be used to study physiological flow conditions inside the phantom. The tubing (36) of the inlet (16) and outlet (18) have the same inner diameter as that of the vessel (26), thus ensuring a smooth geometric transition between the lumen of the vessel (26) and the tubing (36). This has the advantage of minimizing perturbations of the flow that would result from any tubing diameter mismatch.
- Referring now to FIG. 1, for imaging with an apparatus using ultrasonography, the phantom (1) is preferably provided with a removable basin (42) on top thereof. The basin (42) has sides which are preferably formed by a rectangular-shaped wall (44) made in one piece of plexiglass. For assuring watertightness of the basin (42), the wall (44) is sit on a rectangular rubber seal (46) and press down against the cover (28) so as to squeeze the rubber seal (46) by means of two bars (48) leaning on the wall (44) and being screwed in the container (10) by a screw (50) at each opposite end thereof. It should be understood that the bottom of the basin (42) is embodied by the cover (28). Water is poured in the basin (42) and the extremity of an ultrasonic probe (not shown) of the apparatus using ultrasonography is immersed in the water for imaging. Alternatively, the water can be replaced by an acoustic gel. For ultrasound imaging, it is also important to avoid air pocket under the cover (28). To do so, water is added on top of the second layer (24) until the container (10) is full and then the cover (28) is secured to the container (10). The basin (42) is used only for ultrasound imaging and is removed when the phantom (1) is imaged in any other modality.
- Referring now to FIG. 4, according to a preferred embodiment of the invention, the tissue-mimicking material of the second layer (24) is a gel of agar. Such agar gel is composed of 3 weight percent of agar, 8 weight percent of glycerol, 3 weight percent of cellulose particles, and 86 weight percent of degassed water. Glycerol is added to the mixture to increase the acoustic velocity of the gel, so that it is close to the value in living tissues being of 1540 m/s. The cellulose particles, which are preferably the ones bought under the trademark Sigmacell™ of Sigma Chemical, are added as an ultrasound scattering agent to provide better contrast between the vessel (26) and the second layer (24) in B-mode ultrasonic imaging. In a first step for preparing the agar gel, agar, glycerol and water are mixed together. The resulting mixture is stirred and heated until the agar powder is completely dissolved and a clear gelling liquid is obtained. Then, cellulose is added, the mixture is stirred again, and cooled down to the proper temperature for pouring into the container (10) of the phantom (1), i.e. 45° C.
- Still according to a preferred embodiment of the invention, the tissue-mimicking material of the first layer (20) is a gel of agar containing a paraffinic oil which is prepared as follow. Firstly, a volume V of a gel of agar/water/glycerol in the same proportions as for the tissue-mimicking material of the second layer (24) described above, is prepared. Then a volume ranging between V/2 and V of paraffinic oil is added. The mixture is heated and energetically stirred until the gel-oil emulsion becomes stable, i.e. water and oil do not separate after stirring. No cellulose particle is added. As the agar gel contains a great amount of water, mixing them with a high proportion of oil or fat component can be difficult because of problems of homogeneity of the mixture resulting in the apparition of oil bubbles inside the gel matrix, and, with excessive oil concentration, the resulting mixture may not be able to harden. For these reasons, although high oil concentrations provide better contrast with markers, the proportion of oil included in the preparation of the gel is preferably selected in the range 33-50% in volume.
- Accordingly to a preferred embodiment of the present invention, agar-paraffinic oil mixture of the material of the first layer (20) and glass were found to be a suitable set of materials for fulfill the imaging conditions described above i.e. differences of acoustic impedance, X-ray absorption coefficient and MR axial relaxation time. Any other materials and especially other oils or fat components, and other kinds of glass, meeting such imaging conditions, may be suitable for the present invention.
- Referring to FIGS. 2 and 4, the present invention is also directed to a process for manufacturing a multimodality imaging phantom for calibrating an imaging apparatus. Such process comprises the following steps (a) to (e).
- Step (a) is providing a container (10) having walls (12) allowing a use of the imaging apparatus (not shown) for imaging the interior (14) thereof. The walls (12) are provided with at least one set of inlet (16) and outlet (18) as described above.
- Step (b) is providing a first layer (20) containing a first tissue mimicking material in a portion of the interior (14) of the container (10).
- Step (c) is embedding at least one marker (22) in the first layer (20) where the at least one marker (22) has an acoustic impedance that is 3 to 30 times higher than that of the first layer (20), an X-ray absorption coefficient that is 3 to 50 times higher than that of the first layer (20), and a MR axial relaxation time that is 2 to 20 times lower than that of the first layer (20).
- Step (d) is providing a second layer (24) containing a second tissue mimicking material in the remaining portion of the interior (14) of the container (10).
- Step (e) is embedding a vessel (26) in the second layer (24). The vessel (26) is operatively connected to the inlet (16) and the outlet (18) of the container (10).
- Referring now to FIGS. 2, 4,9, 10 and 11, for providing the second layer (24) and embedding the vessel (26) therein, the steps (d) and (e) preferably comprise the following sub-steps (i) to (vi).
- Sub-step (i) is molding a simulating piece (52). In FIG. 11, two simulating pieces (52) are installed in the phantom (1) and the second layer (24) is not provided yet. The simulating piece (52) has an exterior shape simulating the vessel (26) to be formed. The simulating piece (52) is made of a molding material having a melting point lower than the melting point of the second tissue mimicking material. In a preferred embodiment of the invention, the molding material is a cerollow alloy which is preferably a cerro-indium alloy having the trademark Cerrolow 136™ sold by Cerrometal Products, Bellefonte, Pa., USA and having a melting point of 58° C. The simulating piece (52) is prepared by pouring the molding material in a liquid state in the aluminium mold (54) shown in FIG. 9. The mold (54) is made of two parts (56 and 58) that fit over each other. The interior face (57 and 59) of each part (56 and 58) of the mold (54) is shown in FIG. 9 as well as the half of five cavities (60) for pouring the molding material and forming five simulating pieces (52). After casting, the cerollow alloy, which is the preferred molding material, is cooled at room temperature for two hours. It is then extracted from the mold (54) and hand-polished to remove surface irregularities as illustrated in FIG. 10. As it can be appreciated in the preferred embodiment of the mold (54) illustrated in FIG. 9, simulating pieces (52) with different stenoses (62) can be prepared. It should be understood that it is possible to prepare a simulating piece (52) of known controlled geometry that simulates any vascular pathologies with no axis of symmetry. For example, one of the simulating pieces (52) shown in the phantom (1) illustrated in FIG. 11 has only one stenosis (62).
- Sub-step (ii) is coating the simulating piece with a latex layer. The stimulating piece (52) is previously coated with a thin impermeable material, being preferably a latex layer, at the end of sub-step (i). In such an embodiment, the latex layer forms the wall of the vessel (26) which stays intact after removal of the moten cerollow alloy. This latex layer prevents diffusion into the second layer (24) of a contrast agent used in the fluid.
- Sub-step (iii) is connecting one end (51) of the simulating piece (52) to the inlet (16) of the container (10) and another end (53) of the simulating piece (52) to the outlet (18) of the container (10).
- Sub-step (iv) is pouring the second tissue mimicking material, while in a liquid state, in the remaining portion of the interior (14) of the container (10) so as to form the second layer (24) and embed the simulating piece (52). FIG. 11 represents the state of a phantom (1) just before executing sub-step (iv).
- Sub-step (v) is lowering the temperature of the second tissue mimicking material under its melting point so that the second tissue mimicking material becomes solid.
- Sub-step (vi) is melting and removing the simulating piece (52) by heating said simulating piece (52) at a temperature higher than the melting point of the molding material and lower than the melting point of the second tissue mimicking material.
- According to a preferred embodiment of the invention, the simulating piece (52) is made of a cerollow alloy and the second tissue mimicking material is made of a gel of agar. In such a preferred embodiment, removing the simulating piece by heating is advantageously performed as follow. After the second tissue mimicking material is solidified and the cover (28) is secured to the container (10), the phantom (1) is heated in a water bath for several hours. The phantom (1) is installed in the water bath so that the inlet (16) and outlet (18) are vertically positioned and not in contact with the bottom of the bath that is kept at 65° C. As the temperature inside the phantom reaches 58° C., the cerollow alloy starts melting out of the phantom (1) via the inlet (16) or the outlet (18) depending which one is underneath. Removal of the molten cerollow alloy creates in the gel an empty conduit having the shape of the initial simulating piece (26). Such conduit is called the vessel (26). Small residual cerollow particles can be removed by injection of water at 65° C. in the vessel (26) with a syringe.
- Sub-steps (i) to (vi) are a description of the lost-material casting technique for manufacturing a vessel (26). Other techniques to provide a vessel (26) can be used as any one known in the art. Even a real blood vessel can be used.
- Referring now to FIGS. 2, 4,5, 6, 7, and 8, for providing the first layer (20) and embedding the at least one marker (22) in it, steps (b) and (c) preferably comprise the following sub-steps (vii) to (xvi).
- Sub-step (vii) is pouring an amount of the first tissue mimicking material, while in a liquid state, in the portion of the interior (14) of the container (10) mentioned in step (b). The first tissue mimicking material has a melting point. According to a preferred embodiment of the invention, the amount of the first tissue mimicking material that is poured represents between 70% to 90% of the total amount forming the first layer (20).
- Sub-step (viii) is placing a first template (64) on the amount of the first tissue mimicking material. The top surface (66) and the bottom surface (68) of the first template (64) according to a preferred embodiment of the invention, are illustrated in FIGS. 5 and 6 respectively. As it can be seen from FIG. 6, the bottom surface (68) of the first template (64) has a semi-cylindrical shape. The shape of the first template (64) is designed to follow the interior (14) of the container (10) so that the first tissue mimicking material forms a layer of equal thickness, when solidified. Two alignment pins (65) on the first template (64), shown in FIG. 6, and corresponding holes (11) in the container (10), shown in FIG. 3, ensure a correct positioning of the first template (64) onto the container (10). The first template (64) has at least one pin (70) removably fixed thereto and extending in the first tissue mimicking material. In the preferred embodiment shown in FIG. 6, twenty-five pins (70) extend form the bottom surface (68) of the first template (64). The pin (70) is advantageously a screw and the head screw (72) is shown on the top surface (66) illustrated in FIG. 5.
- Sub-step (ix) is lowering the temperature of the first tissue mimicking material under its melting point so that the first tissue mimicking material becomes solid.
- Sub-step (x) is removing the at least one pin (70) so as to free at least one recess (not shown) in the solid first tissue mimicking material. According to the preferred embodiment of the pin (70) which is a screw, removing the pin (70) consists in screw off the pin (70).
- Sub-step (xi) is placing the at least one marker (22) in the at least one recess respectively. Preferably, the recess has the same shape than the marker (22). Thus according to a preferred embodiment where the marker (22) is a ball of 3 mm of diameter, the recess has a depth of 6 mm, a circular periphery, a width of 3 mm and a round bottom for snugly fitting the marker (22).
- Sub-step (xii) is removing the first template (64).
- Sub-step (xiii) is pouring another amount of the first tissue mimicking material, while in a liquid state.
- Sub-step (xiv) is placing a second template (74) on the first tissue mimicking material poured in sub-step (viii) so that the another amount of the first tissue mimicking material covers the at least one marker (22) and fills remaining portion of the at least one recess so as to surround completely the at least one marker (22). The bottom surface (76) and the top surface (78) of the second template (74) according to a preferred embodiment of the invention are illustrated in FIGS. 7 and 8 respectively. As it can be seen from FIG. 7, the bottom surface (76) has a semi-cylindrical shape which is designed to follow the top surface of the solidified amount of first tissue mimicking material and therefore providing a first layer (20) of equal thickness. Two alignment pins (75) on the second template (74) (shown in FIG. 7) and corresponding holes (11) in the container (10) (shown in FIG. 3) ensure a correct positioning of the second template (74) onto the container (10).
- Sub-step (xv) is lowering the temperature of the first tissue mimicking material poured in step (xiii) under its melting point so that it becomes solid. After solidification, the two amounts of the first tissue mimicking material cannot be distinguished from one another, both visually and on the acquired images obtained from apparatuses of all modalities.
- Sub-step (xvi) is removing the second template (74). Then, the second layer (24) is provided as described above in step (d). According to the preferred embodiment where the second tissue mimicking material is a gel of agar and the molding material of the simulating piece (52) is a Cerrolow 136™, the gel of agar is poured at 45° C. This temperature was found to be a good compromise because it is high enough to allow pouring before solidifying, and it is sufficiently low, compared with the melting point of Cerrolow 136™, to avoid softening and deformation of the simulating piece. The gel of agar is then allowed to solidify at room temperature for approximately 10 hours.
- Although preferred embodiments of the invention have been described in detail herein and illustrated in the accompanying drawings, it is to be understood that the invention is not limited to the precise embodiments and that various changes and modifications may be effected therein without departing from the scope or the spirit of the invention.
Claims (20)
Priority Applications (4)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US10/010,886 US20030086535A1 (en) | 2001-11-08 | 2001-11-08 | Multimodality imaging phantom and process for manufacturing said phantom |
US10/495,407 US7439493B2 (en) | 2001-11-08 | 2002-11-05 | Multimodality imaging phantom and process for manufacturing said phantom |
PCT/CA2002/001633 WO2003040745A1 (en) | 2001-11-08 | 2002-11-05 | Multimodality imaging phantom and process for manufacturing said phantom |
CA002466100A CA2466100A1 (en) | 2001-11-08 | 2002-11-05 | Multimodality imaging phantom and process for manufacturing said phantom |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US10/010,886 US20030086535A1 (en) | 2001-11-08 | 2001-11-08 | Multimodality imaging phantom and process for manufacturing said phantom |
Related Child Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US10/495,407 Continuation-In-Part US7439493B2 (en) | 2001-11-08 | 2002-11-05 | Multimodality imaging phantom and process for manufacturing said phantom |
Publications (1)
Publication Number | Publication Date |
---|---|
US20030086535A1 true US20030086535A1 (en) | 2003-05-08 |
Family
ID=21747879
Family Applications (2)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US10/010,886 Abandoned US20030086535A1 (en) | 2001-11-08 | 2001-11-08 | Multimodality imaging phantom and process for manufacturing said phantom |
US10/495,407 Expired - Fee Related US7439493B2 (en) | 2001-11-08 | 2002-11-05 | Multimodality imaging phantom and process for manufacturing said phantom |
Family Applications After (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US10/495,407 Expired - Fee Related US7439493B2 (en) | 2001-11-08 | 2002-11-05 | Multimodality imaging phantom and process for manufacturing said phantom |
Country Status (3)
Country | Link |
---|---|
US (2) | US20030086535A1 (en) |
CA (1) | CA2466100A1 (en) |
WO (1) | WO2003040745A1 (en) |
Cited By (29)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20020134133A1 (en) * | 2001-03-21 | 2002-09-26 | Fuji Photo Film Co., Ltd. | Ultrasonic diagnostic apparatus and method of checking its performance |
US20030021381A1 (en) * | 2001-07-25 | 2003-01-30 | Reiner Koppe | Method and device for the registration of two 3D image data sets |
US20050028482A1 (en) * | 2003-07-01 | 2005-02-10 | Xenogen Corporation | Multi-mode internal imaging |
US20050225004A1 (en) * | 2004-04-08 | 2005-10-13 | May Gregory J | Identifiable structures and systems and methods for forming the same in a solid freeform fabrication system |
US20070125177A1 (en) * | 2005-12-01 | 2007-06-07 | The Boeing Company | Tapered ultrasonic reference standard |
US20070238946A1 (en) * | 2006-02-03 | 2007-10-11 | Chiodo Chris D | Specimen positioning system for imaging machines |
WO2008030475A2 (en) * | 2006-09-08 | 2008-03-13 | Varian, Inc. | Magnetic resonance phantom systems and methods |
US20080265882A1 (en) * | 2007-04-24 | 2008-10-30 | General Hospital Corporation | Phantom for use in magnetic resonance imaging studies |
US20090316972A1 (en) * | 2008-01-14 | 2009-12-24 | Borenstein Jeffrey T | Engineered phantoms for perfusion imaging applications |
DE102009017071A1 (en) | 2009-04-01 | 2010-10-14 | Schott Ag | Phantom standard for e.g. examining tissue samples, has transparent substrate designed in form of plate made from glass ceramics or glass, and layer comprising barium sulfate, where barium sulfate is mixed with binder to form paste |
EP2510878A1 (en) * | 2011-04-12 | 2012-10-17 | Marcus Abboud | Method for generating a radiological three dimensional digital volume tomography image of part of a patient's body |
EP2578155A1 (en) * | 2011-10-05 | 2013-04-10 | General Electric Company | X-ray calibration device |
WO2014140547A1 (en) * | 2013-03-11 | 2014-09-18 | King's College London | Perfusion phantom device |
US20140294140A1 (en) * | 2011-05-12 | 2014-10-02 | The Regents Of The University Of California | Radiographic phantom apparatuses |
US20150085993A1 (en) * | 2013-09-26 | 2015-03-26 | Varian Medical Systems International Ag | Dosimetric end-to-end verification devices, systems, and methods |
ITRM20130701A1 (en) * | 2013-12-20 | 2015-06-21 | I R C C S Ct Neurolesi Bonino Pulejo | UNIVERSAL FANTOCCIO STRUCTURE FOR QUALITY CONTROL IN COMPUTERIZED TOMOGRAPHY AND MAGNETIC RESONANCE |
US9179884B2 (en) | 2010-12-31 | 2015-11-10 | General Electric Company | Normalized metrics for visceral adipose tissue mass and volume estimation |
US20150323639A1 (en) * | 2014-10-16 | 2015-11-12 | National Institute Of Standards And Technology | Mri phantom, method for making same and acquiring an mri image |
US9254101B2 (en) | 2010-12-31 | 2016-02-09 | General Electric Company | Method and system to improve visceral adipose tissue estimate by measuring and correcting for subcutaneous adipose tissue composition |
US9271690B2 (en) | 2010-12-31 | 2016-03-01 | General Electric Company | Method and system to estimate visceral adipose tissue by restricting subtraction of subcutaneous adipose tissue to coelom projection region |
US20160245705A1 (en) * | 2013-10-04 | 2016-08-25 | Battelle Memorial Institute | Contrast phantom for passive millimeter wave imaging systems |
US9625584B1 (en) * | 2015-11-20 | 2017-04-18 | Wisconsin Alumni Research Foundation | Systems and methods for a linearly filled nuclear imaging phantom |
US20170276824A1 (en) * | 2014-09-26 | 2017-09-28 | Battelle Memorial Institute | Image quality test article set |
US20180035962A1 (en) * | 2015-04-26 | 2018-02-08 | Baylor College Of Medicine | Phantoms and methods and kits using the same |
US10578702B2 (en) * | 2015-10-02 | 2020-03-03 | Uab Research Foundation | Imaging phantom and systems and methods of using same |
US20200170612A1 (en) * | 2017-08-17 | 2020-06-04 | Technological University Dublin | Tissue Mimicking Materials |
US11176848B1 (en) | 2020-05-29 | 2021-11-16 | Endra Life Sciences Inc. | Tissue-mimicking material for a multi-modality imaging phantom |
US11373552B2 (en) * | 2017-08-17 | 2022-06-28 | Virginia Commonwealth University | Anatomically accurate brain phantoms and methods for making and using the same |
US11885927B2 (en) | 2014-09-26 | 2024-01-30 | Battelle Memorial Institute | Image quality test article |
Families Citing this family (9)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
KR100517889B1 (en) * | 2003-05-09 | 2005-09-30 | 주라형 | Phantom for accuracy evaluation of image registration |
US7697738B2 (en) | 2003-08-25 | 2010-04-13 | Koninklijke Philips Electronics N.V. | Calibration image alignment in a PET-CT system |
DE102004011744A1 (en) * | 2004-03-03 | 2005-09-22 | Aesculap Ag & Co. Kg | A surgical or medical device and method for calibrating an ultrasonic sensor |
FR2903211B1 (en) * | 2006-06-30 | 2009-03-06 | Gen Electric | METHODS AND DEVICES FOR CORRECTING IMPLANT MAMMOGRAPHY AND SEGMENTING AN IMPLANT |
WO2008075303A1 (en) * | 2006-12-21 | 2008-06-26 | Koninklijke Philips Electronics N.V. | Anatomically and functionally accurate soft tissue phantoms and method for generating same |
US7965080B2 (en) * | 2008-09-18 | 2011-06-21 | Siemens Medical Solutions Usa, Inc. | Electro-conductive pet phantom for MR/PET quality control measurement |
US8888498B2 (en) | 2009-06-02 | 2014-11-18 | National Research Council Of Canada | Multilayered tissue phantoms, fabrication methods, and use |
CN104856675B (en) * | 2015-06-08 | 2017-06-09 | 中国医学科学院生物医学工程研究所 | Imitative body for magnetosonic coupled signal test experience prepares device and method |
US11510658B2 (en) * | 2019-06-05 | 2022-11-29 | Wisconsin Alumni Research Foundation | Systems and methods for a multi-modality phantom having an interchangeable insert |
Family Cites Families (14)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4331021A (en) * | 1980-09-11 | 1982-05-25 | The United States Of America As Represented By The Secretary Of The Department Of Health And Human Services | Contrast resolution tissue equivalent ultrasound test object |
US4499375A (en) * | 1982-05-10 | 1985-02-12 | Jaszczak Ronald J | Nuclear imaging phantom |
US4551678A (en) * | 1982-11-26 | 1985-11-05 | Morgan Tommie J | Phantom for nuclear magnetic resonance machine |
US4724110A (en) * | 1983-11-28 | 1988-02-09 | Arnold Ben A | Method of making a test phantom |
US4644276A (en) * | 1984-09-17 | 1987-02-17 | General Electric Company | Three-dimensional nuclear magnetic resonance phantom |
US4843866A (en) * | 1986-10-06 | 1989-07-04 | Wisconsin Alumni Research Foundation | Ultrasound phantom |
US4794631A (en) * | 1986-10-06 | 1988-12-27 | Vari-X, Inc. | Cardiovascular phantom |
US4985906A (en) * | 1987-02-17 | 1991-01-15 | Arnold Ben A | Calibration phantom for computer tomography system |
CA1311520C (en) * | 1989-02-24 | 1992-12-15 | Ernest L. Madsen | Contrast resolution tissue mimicking phantoms for nuclear magetic resonance imaging |
KR0128168B1 (en) * | 1993-12-18 | 1998-04-04 | 김광호 | Paper saving device for printer |
US5560242A (en) * | 1994-08-16 | 1996-10-01 | Flextech Systems, Inc. | Ultrasonic system evaluation phantoms |
US5793835A (en) * | 1997-03-19 | 1998-08-11 | Blanck; Cheryl A. | Quality assurance phantom for tomography and method of use |
JP2001000430A (en) | 1999-06-24 | 2001-01-09 | Alcare Co Ltd | Marker for image photographing |
US6318146B1 (en) * | 1999-07-14 | 2001-11-20 | Wisconsin Alumni Research Foundation | Multi-imaging modality tissue mimicking materials for imaging phantoms |
-
2001
- 2001-11-08 US US10/010,886 patent/US20030086535A1/en not_active Abandoned
-
2002
- 2002-11-05 WO PCT/CA2002/001633 patent/WO2003040745A1/en not_active Application Discontinuation
- 2002-11-05 CA CA002466100A patent/CA2466100A1/en not_active Abandoned
- 2002-11-05 US US10/495,407 patent/US7439493B2/en not_active Expired - Fee Related
Cited By (58)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20020134133A1 (en) * | 2001-03-21 | 2002-09-26 | Fuji Photo Film Co., Ltd. | Ultrasonic diagnostic apparatus and method of checking its performance |
US6883362B2 (en) * | 2001-03-21 | 2005-04-26 | Fuji Photo Film Co., Ltd. | Ultrasonic diagnostic apparatus and method of checking its performance |
US6999811B2 (en) * | 2001-07-25 | 2006-02-14 | Koninklijke Philips Electronics N.V. | Method and device for the registration of two 3D image data sets |
US20030021381A1 (en) * | 2001-07-25 | 2003-01-30 | Reiner Koppe | Method and device for the registration of two 3D image data sets |
US7881773B2 (en) | 2003-07-01 | 2011-02-01 | Xenogen Corporation | Multi-mode internal imaging |
US20110092813A1 (en) * | 2003-07-01 | 2011-04-21 | Xenogen Corporation | Multi-mode internal imaging |
US20060253013A1 (en) * | 2003-07-01 | 2006-11-09 | Xenogen Corporation | Multi-mode internal imaging |
US20060258941A1 (en) * | 2003-07-01 | 2006-11-16 | Xenogen Corporation | Multi-mode internal imaging |
US7190991B2 (en) | 2003-07-01 | 2007-03-13 | Xenogen Corporation | Multi-mode internal imaging |
US9008758B2 (en) | 2003-07-01 | 2015-04-14 | Xenogen Corporation | Multi-mode internal imaging |
US7813782B2 (en) | 2003-07-01 | 2010-10-12 | Xenogen Corporation | Imaging system including an object handling system |
US20050028482A1 (en) * | 2003-07-01 | 2005-02-10 | Xenogen Corporation | Multi-mode internal imaging |
US7357887B2 (en) | 2004-04-08 | 2008-04-15 | Hewlett-Packard Development Company, L.P. | Identifiable structures and systems and methods for forming the same in a solid freeform fabrication system |
US20050225004A1 (en) * | 2004-04-08 | 2005-10-13 | May Gregory J | Identifiable structures and systems and methods for forming the same in a solid freeform fabrication system |
US20070125177A1 (en) * | 2005-12-01 | 2007-06-07 | The Boeing Company | Tapered ultrasonic reference standard |
US7762120B2 (en) * | 2005-12-01 | 2010-07-27 | The Boeing Company | Tapered ultrasonic reference standard |
US20070238946A1 (en) * | 2006-02-03 | 2007-10-11 | Chiodo Chris D | Specimen positioning system for imaging machines |
US7865226B2 (en) * | 2006-02-03 | 2011-01-04 | Chiodo Chris D | Specimen positioning system for imaging machines |
WO2008030475A2 (en) * | 2006-09-08 | 2008-03-13 | Varian, Inc. | Magnetic resonance phantom systems and methods |
US8072217B2 (en) | 2006-09-08 | 2011-12-06 | Agilent Technologies, Inc. | Magnetic resonance phantom systems and methods |
WO2008030475A3 (en) * | 2006-09-08 | 2008-08-14 | Varian Inc | Magnetic resonance phantom systems and methods |
US7612560B2 (en) | 2007-04-24 | 2009-11-03 | The General Hospital Corporation | Selectively adjustable phantom that is compatible with a magnetic resonance imaging system and environment |
US20080265882A1 (en) * | 2007-04-24 | 2008-10-30 | General Hospital Corporation | Phantom for use in magnetic resonance imaging studies |
US20090316972A1 (en) * | 2008-01-14 | 2009-12-24 | Borenstein Jeffrey T | Engineered phantoms for perfusion imaging applications |
US8188416B2 (en) | 2008-01-14 | 2012-05-29 | The Charles Stark Draper Laboratory, Inc. | Engineered phantoms for perfusion imaging applications |
DE102009017071A1 (en) | 2009-04-01 | 2010-10-14 | Schott Ag | Phantom standard for e.g. examining tissue samples, has transparent substrate designed in form of plate made from glass ceramics or glass, and layer comprising barium sulfate, where barium sulfate is mixed with binder to form paste |
US9271690B2 (en) | 2010-12-31 | 2016-03-01 | General Electric Company | Method and system to estimate visceral adipose tissue by restricting subtraction of subcutaneous adipose tissue to coelom projection region |
US9254101B2 (en) | 2010-12-31 | 2016-02-09 | General Electric Company | Method and system to improve visceral adipose tissue estimate by measuring and correcting for subcutaneous adipose tissue composition |
US9179884B2 (en) | 2010-12-31 | 2015-11-10 | General Electric Company | Normalized metrics for visceral adipose tissue mass and volume estimation |
EP2510878A1 (en) * | 2011-04-12 | 2012-10-17 | Marcus Abboud | Method for generating a radiological three dimensional digital volume tomography image of part of a patient's body |
US8831322B2 (en) | 2011-04-12 | 2014-09-09 | Marcus Abboud | Method of generating a three-dimensional digital radiological volume topography recording of a patient's body part |
US20140294140A1 (en) * | 2011-05-12 | 2014-10-02 | The Regents Of The University Of California | Radiographic phantom apparatuses |
US9398889B2 (en) * | 2011-05-12 | 2016-07-26 | The Regents Of The University Of California | Radiographic phantom apparatuses |
EP2578155A1 (en) * | 2011-10-05 | 2013-04-10 | General Electric Company | X-ray calibration device |
US9990863B2 (en) | 2013-03-11 | 2018-06-05 | King's College London | Perfusion phantom device |
WO2014140547A1 (en) * | 2013-03-11 | 2014-09-18 | King's College London | Perfusion phantom device |
US9643029B2 (en) * | 2013-09-26 | 2017-05-09 | Varian Medical Systems International Ag | Dosimetric end-to-end verification devices, systems, and methods |
US20150085993A1 (en) * | 2013-09-26 | 2015-03-26 | Varian Medical Systems International Ag | Dosimetric end-to-end verification devices, systems, and methods |
US10463885B2 (en) | 2013-09-26 | 2019-11-05 | Varian Medical Systems International Ag | Dosimetric end-to-end verification devices, systems, and methods |
US10197451B2 (en) * | 2013-10-04 | 2019-02-05 | Battelle Memorial Institute | Contrast phantom for passive millimeter wave imaging systems |
US20160245705A1 (en) * | 2013-10-04 | 2016-08-25 | Battelle Memorial Institute | Contrast phantom for passive millimeter wave imaging systems |
ITRM20130701A1 (en) * | 2013-12-20 | 2015-06-21 | I R C C S Ct Neurolesi Bonino Pulejo | UNIVERSAL FANTOCCIO STRUCTURE FOR QUALITY CONTROL IN COMPUTERIZED TOMOGRAPHY AND MAGNETIC RESONANCE |
US10168409B2 (en) | 2013-12-20 | 2019-01-01 | I.R.C.C.S. Centro Neurolesi “Bonino-Pulejo” | Universal phantom structure for quality inspections both on computerized tomography and on magnetic resonance tomography |
WO2015092776A1 (en) * | 2013-12-20 | 2015-06-25 | I.R.C.C.S. Centro Neurolesi "Bonino-Pulejo" | Universal phantom structure for quality inspections both on computerized tomography and on magnetic resonance tomography |
US11614559B2 (en) | 2014-09-26 | 2023-03-28 | Battelle Memorial Institute | Image quality test article set |
US20170276824A1 (en) * | 2014-09-26 | 2017-09-28 | Battelle Memorial Institute | Image quality test article set |
US11885927B2 (en) | 2014-09-26 | 2024-01-30 | Battelle Memorial Institute | Image quality test article |
US10871591B2 (en) * | 2014-09-26 | 2020-12-22 | Battelle Memorial Institute | Image quality test article set |
US20150323639A1 (en) * | 2014-10-16 | 2015-11-12 | National Institute Of Standards And Technology | Mri phantom, method for making same and acquiring an mri image |
US10082553B2 (en) * | 2014-10-16 | 2018-09-25 | National Institute Of Standards And Technology | MRI phantom, method for making same and acquiring an MRI image |
US20180035962A1 (en) * | 2015-04-26 | 2018-02-08 | Baylor College Of Medicine | Phantoms and methods and kits using the same |
US10426418B2 (en) * | 2015-04-26 | 2019-10-01 | Baylor College Of Medicine | Phantoms and methods and kits using the same |
US10578702B2 (en) * | 2015-10-02 | 2020-03-03 | Uab Research Foundation | Imaging phantom and systems and methods of using same |
US9625584B1 (en) * | 2015-11-20 | 2017-04-18 | Wisconsin Alumni Research Foundation | Systems and methods for a linearly filled nuclear imaging phantom |
US20200170612A1 (en) * | 2017-08-17 | 2020-06-04 | Technological University Dublin | Tissue Mimicking Materials |
US11373552B2 (en) * | 2017-08-17 | 2022-06-28 | Virginia Commonwealth University | Anatomically accurate brain phantoms and methods for making and using the same |
WO2021242649A1 (en) * | 2020-05-29 | 2021-12-02 | Endra Life Sciences Inc. | Tissue-mimicking material for a multi-modality imaging phantom |
US11176848B1 (en) | 2020-05-29 | 2021-11-16 | Endra Life Sciences Inc. | Tissue-mimicking material for a multi-modality imaging phantom |
Also Published As
Publication number | Publication date |
---|---|
US7439493B2 (en) | 2008-10-21 |
US20050123178A1 (en) | 2005-06-09 |
CA2466100A1 (en) | 2003-05-15 |
WO2003040745A1 (en) | 2003-05-15 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
US7439493B2 (en) | Multimodality imaging phantom and process for manufacturing said phantom | |
Filippou et al. | Recent advances on the development of phantoms using 3D printing for imaging with CT, MRI, PET, SPECT, and ultrasound | |
Fahrig et al. | A three‐dimensional cerebrovascular flow phantom | |
Cloutier et al. | A multimodality vascular imaging phantom with fiducial markers visible in DSA, CTA, MRA, and ultrasound | |
US6205871B1 (en) | Vascular phantoms | |
JP2010513977A (en) | Anatomically and functionally accurate soft tissue phantom and method for producing the same | |
CA2494588C (en) | Three-dimensional model | |
Zhou et al. | Fabrication of two flow phantoms for Doppler ultrasound imaging | |
Chen et al. | An anthropomorphic polyvinyl alcohol brain phantom based on Colin27 for use in multimodal imaging | |
Smith et al. | Anthropomorphic carotid bifurcation phantom for MRI applications | |
Rethy et al. | Anthropomorphic liver phantom with flow for multimodal image-guided liver therapy research and training | |
Gailloud et al. | An in vitro anatomic model of the human cerebral arteries with saccular arterial aneurysms | |
Lennie et al. | Multimodal phantoms for clinical PET/MRI | |
Sommer et al. | Method to simulate distal flow resistance in coronary arteries in 3D printed patient specific coronary models | |
Nisar et al. | A simple, realistic walled phantom for intravascular and intracardiac applications | |
Paulsen et al. | Projection-based stereolithography for direct 3D printing of heterogeneous ultrasound phantoms | |
US7812605B2 (en) | Test object for nuclear spin tomographs | |
Kampmann et al. | 3-D sonographic volume measurement of the cerebral ventricular system: in vitro validation | |
Martínez et al. | 3D perfused brain phantom for interstitial ultrasound thermal therapy and imaging: design, construction and characterization | |
Allard et al. | Multimodality vascular imaging phantoms: A new material for the fabrication of realistic 3D vessel geometries | |
CN113724562B (en) | Simulated craniocerebral model for transcranial ultrasonic scanning and preparation method thereof | |
Cheung et al. | Magnetic resonance imaging properties of multimodality anthropomorphic silicone rubber phantoms for validating surgical robots and image guided therapy systems | |
Walter et al. | Use of a simple, inexpensive dual‐modality phantom as a learning tool for magnetic resonance imaging–ultrasound fusion techniques | |
Pirozzi et al. | 3D-printed anatomical phantoms | |
JP2005040299A (en) | Production method for flow field visualization apparatus and liquid channel model, and blood flow simulation method |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
AS | Assignment |
Owner name: CENTRE HOSPITALIER DE L'UNIVERSITE DE MONTREAL, CA Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:TEPPAZ, PIERRE;QANADLI, SALAH DINE;CLOUTIER, GUY;AND OTHERS;REEL/FRAME:012889/0829;SIGNING DATES FROM 20020205 TO 20020308 Owner name: UNIVERSITE DE MONTREAL, CANADA Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:TEPPAZ, PIERRE;QANADLI, SALAH DINE;CLOUTIER, GUY;AND OTHERS;REEL/FRAME:012889/0829;SIGNING DATES FROM 20020205 TO 20020308 Owner name: INSTITUT DE RECHERCHES CLINIQUES DE MONTREAL, CANA Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:TEPPAZ, PIERRE;QANADLI, SALAH DINE;CLOUTIER, GUY;AND OTHERS;REEL/FRAME:012889/0829;SIGNING DATES FROM 20020205 TO 20020308 |
|
STCB | Information on status: application discontinuation |
Free format text: ABANDONED -- FAILURE TO RESPOND TO AN OFFICE ACTION |