WO2016081677A1 - Schéma d'imagerie et de marquage pulsé stationnaire pour perfusion non invasive - Google Patents

Schéma d'imagerie et de marquage pulsé stationnaire pour perfusion non invasive Download PDF

Info

Publication number
WO2016081677A1
WO2016081677A1 PCT/US2015/061460 US2015061460W WO2016081677A1 WO 2016081677 A1 WO2016081677 A1 WO 2016081677A1 US 2015061460 W US2015061460 W US 2015061460W WO 2016081677 A1 WO2016081677 A1 WO 2016081677A1
Authority
WO
WIPO (PCT)
Prior art keywords
slice
magnetization
image
labeling
images
Prior art date
Application number
PCT/US2015/061460
Other languages
English (en)
Inventor
Peter Van Zijl
Jiadi XU
James J. PEKAR
Ying Cheng
Original Assignee
The Johns Hopkins University
Kennedy Krieger Institute, Inc.
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by The Johns Hopkins University, Kennedy Krieger Institute, Inc. filed Critical The Johns Hopkins University
Publication of WO2016081677A1 publication Critical patent/WO2016081677A1/fr

Links

Classifications

    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B5/00—Measuring for diagnostic purposes; Identification of persons
    • A61B5/02—Detecting, measuring or recording pulse, heart rate, blood pressure or blood flow; Combined pulse/heart-rate/blood pressure determination; Evaluating a cardiovascular condition not otherwise provided for, e.g. using combinations of techniques provided for in this group with electrocardiography or electroauscultation; Heart catheters for measuring blood pressure
    • A61B5/026—Measuring blood flow
    • A61B5/0263—Measuring blood flow using NMR
    • 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
    • G01R33/54—Signal processing systems, e.g. using pulse sequences ; Generation or control of pulse sequences; Operator console
    • G01R33/56—Image enhancement or correction, e.g. subtraction or averaging techniques, e.g. improvement of signal-to-noise ratio and resolution
    • G01R33/563—Image enhancement or correction, e.g. subtraction or averaging techniques, e.g. improvement of signal-to-noise ratio and resolution of moving material, e.g. flow contrast angiography
    • G01R33/56366—Perfusion imaging
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B2503/00—Evaluating a particular growth phase or type of persons or animals
    • A61B2503/40—Animals
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B2576/00—Medical imaging apparatus involving image processing or analysis
    • A61B2576/02—Medical imaging apparatus involving image processing or analysis specially adapted for a particular organ or body part
    • A61B2576/026—Medical imaging apparatus involving image processing or analysis specially adapted for a particular organ or body part for the brain
    • 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
    • A61B5/004—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 image acquisition of a particular organ or body part
    • A61B5/0042—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 image acquisition of a particular organ or body part for the brain
    • 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
    • G01R33/483—NMR imaging systems with selection of signals or spectra from particular regions of the volume, e.g. in vivo spectroscopy
    • G01R33/4833—NMR imaging systems with selection of signals or spectra from particular regions of the volume, e.g. in vivo spectroscopy using spatially selective excitation of the volume of interest, e.g. selecting non-orthogonal or inclined slices
    • G01R33/4835—NMR imaging systems with selection of signals or spectra from particular regions of the volume, e.g. in vivo spectroscopy using spatially selective excitation of the volume of interest, e.g. selecting non-orthogonal or inclined slices of multiple slices
    • G—PHYSICS
    • G16—INFORMATION AND COMMUNICATION TECHNOLOGY [ICT] SPECIALLY ADAPTED FOR SPECIFIC APPLICATION FIELDS
    • G16H—HEALTHCARE INFORMATICS, i.e. INFORMATION AND COMMUNICATION TECHNOLOGY [ICT] SPECIALLY ADAPTED FOR THE HANDLING OR PROCESSING OF MEDICAL OR HEALTHCARE DATA
    • G16H30/00—ICT specially adapted for the handling or processing of medical images
    • G16H30/40—ICT specially adapted for the handling or processing of medical images for processing medical images, e.g. editing

Definitions

  • the present invention relates generally to magnetic resonance imaging. More particularly, the present invention relates to a method for multi-slice perfusion imaging with a steady pulsed interleaved labeling and imaging scheme.
  • ASL Arterial spin labeling
  • CBF cerebral blood flow
  • RF radio frequency
  • PASL pulsed ASL
  • CASL continuous ASL
  • VSASL velocity selective ASL
  • CASL is a popular technique, which provides a higher SNR compared to the PASL method due to the ability to attain long bolus durations.
  • MT magnetization transfer
  • the present invention including a method for magnetic resonance imaging of blood flow including applying a labeling and exchange module (LEM), which can be a pair of radiofrequency pulses together with magnet field gradients to change the magnetization of the arterial spins of blood outside of the image area or a train of radiofrequency pulses together with magnet field gradients to change the magnetization of the artery blood with certain flow speeds.
  • LEM labeling and exchange module
  • the method includes waiting a period after the labeling and exchange module to allow a labeled blood transfer to the imaging area.
  • the method also includes acquiring a first slice or few slices of an MR image.
  • the method includes applying the labeling and exchange module and the waiting period, and then recording a second image slice or other multiple slices and repeating the process until all image slices are acquired.
  • the method includes acquiring another multi-slice MRI image by turning off magnetic field gradients in the labeling and exchange module and generating a difference images based on the first slice image and the second slice image to represent a blood flow image of an imaging area.
  • a method for magnetic resonance imaging of blood flow includes applying a labeling and exchange module, which can be a pair of radiofrequency pulses together with magnet field gradients to change the magnetization of the arterial spins of blood outside of the image area or a train of radiofrequency pulses together with magnet field gradients to change the magnetization of the artery blood with certain flow speeds.
  • the method includes waiting a period after each labeling and exchange module to allow labeled blood transfer to the imaging area and repeating the labeling and exchange module and wait period several times to accumulate the labeled blood in the image area.
  • the method includes acquiring a single slice MR image, multi-slice MRI image or 3D MRI image after the previous labeling period.
  • the method includes acquiring another single slice, multi-slice or 3D MRI image by turning off the magnet field gradients in the pair of radiofrequency pulses and generating difference images based on the first slice image and the second slice image to represent a blood flow image of the imaging area.
  • the method includes a radiofrequency pulse that is a frequency-selective excitation or inversion pulse for water.
  • the magnetic field gradients for two radiofrequency pulses are different waveforms to change the magnetization of the arterial spins of blood outside of the image area, while avoiding perturb the magnetization in the image area.
  • the method can include a labeling and exchange module that change the magnetization of the arterial spins with particular blood flow rates using a flow sensitive gradients, while avoiding perturb the magnetization of the stationary spins.
  • the method can also include obtaining the arterial transit time by acquiring MR images using one selected from a group consisting of acquiring images as a function of waiting time after the radiofrequency pulses and acquiring images by taking a difference between different waiting times.
  • a non-transitory computer readable medium is programmed to execute steps including applying a pair of radiofrequency pulses together with different gradient waves and applying different delays after the radiofrequency pulses.
  • the steps include generating images of differences in magnetization change for labeled and control images by turning on and off gradients during the radiofrequency pulses and analyzing a difference in magnetization change as a function of waiting time.
  • FIG. 1A illustrates a graphical view of the steady pulsed imaging and labeling (SPIL) sequence composed of a series of labeling and exchange modules (LEMs), each containing two adiabatic inversion pulses, and followed by a mixing time (tmix) to enable the labeled water spins to perfuse into the tissue in the image slice.
  • SPIL steady pulsed imaging and labeling
  • FIG. IB illustrates a schematic diagram of the inversion slab positions, with respect to the image slice.
  • FIG. 1C illustrates a graphical view of a time diagram of the multi-pulsed imaging and labeling (MPIL) scheme.
  • MPIL multi-pulsed imaging and labeling
  • FIG. ID illustrates a schematic diagram of the inversion slab positions, with respect to the image slices, for the MPIL sequence.
  • FIG. IE illustrates a graphical view of the steady velocity selective pulsed imaging (SVASL) and labeling sequence composed of a series of velocity selective labeling and exchange modules, each containing two 90 degree pulses with two 180 degree refocus pulse in between, and the velocity selective unit followed by a mixing time (tmix) to enable the labeled water spins to perfuse into the tissue in the image slice.
  • SVASL steady velocity selective pulsed imaging
  • FIG. IF illustrates the multi-pulsed velocity selective imaging and labeling sequence (MVASL).
  • FIGS. 2A and 2B illustrate graphical views of the arterial input function (AIF) and the corresponding perfusion signal ( ⁇ / ⁇ ) for the SPIL scheme, respectively.
  • FIG. 2C illustrates a graphical view of the typical AIF for MPIL with the parameters used in FIGS. 2A and 2B.
  • FIG. 2D illustrates a graphical view of the simulated perfusion kinetic curves for the single slice MPIL with 1, 2, and 4 label modules, respectively (1 in dark grey, 2 in medium grey, 4 in light grey).
  • FIG. 3A illustrates control images (Mcontroi) from a post mortem mouse brain. Only three slices located at -3 mm, 0 mm, and 3 mm from the isocenter of the magnet are shown as examples.
  • FIGS. 3B and 3C illustrate difference images (AM/M CO ntroi) recorded using the SPIL scheme, with slab margins of 2 mm in FIG. 3B and 6 mm in FIG. 3C.
  • FIGS. 4A-4E illustrate image and graphical views showing normalized difference images ( ⁇ /Mcontroi) from a healthy mouse brain with different crusher gradient strengths.
  • FIGS. 5A and 5B illustrate graphical views of experimental perfusion kinetic curves, with respect to the total label time.
  • FIG. 6A illustrates images of typical multi-slice ASL images (five slice) of the mouse brain obtained with the SPIL scheme, with one slice in each mixing time and mixing time 1 s. The resolution is 250x250 ⁇ 2 .
  • FIG. 6B illustrates images of typical multi-slice ASL images (ten slice) obtained with the SPIL scheme.
  • FIG. 6B illustrates images of typical multi-slice ASL images (ten slice) of the mouse brain obtained with the SPIL scheme, with four slices in a two seconds mixing time. The resolution is 250x250 ⁇ 2 .
  • FIG. 7 illustrates a graphical view of Bilateral symmetry of CBF for three brain regions in five mice: cortex (triangle), hippocampus (circle), and thalamus (diamond).
  • FIG. 8B illustrates representative multi-slice perfusion maps (bottom row) on postnatal mouse brain with a stroke model, acquired using the SPIL scheme.
  • FIG. 9 illustrates perfusion images of mouse brain recorded on mouse with 9L- gliomas.
  • FIGS. lOA-lOC illustrates a high-resolution perfusion, T2w, Tiw and Apparent Diffusion Coefficient (ADC) map on mouse brain with stroke model.
  • the present invention is directed to a method of steady pulsed imaging and labeling (SPIL) to obtain high-resolution multi-slice perfusion images of brain using standard preclinical MRI equipment.
  • SPIL steady pulsed imaging and labeling
  • the SPIL scheme repeats a pulsed arterial spin labeling (PASL) module together with a short mixing time to extend the temporal duration of the generated PASL bolus to the total experimental time.
  • Multi-slice image acquisition is interleaved with the labeling modules.
  • the mixing time is also used for magnetization recovery following image acquisition.
  • SPIL yields multi-slice perfusion images faster than traditional ASL methods.
  • the perfusion kinetic curve can be measured by multi-pulsed imaging and labeling (MPIL), i. e. acquiring single-slice ASL signal before reaching steady-state in the SPIL sequence.
  • MPIL multi-pulsed imaging and labeling
  • the new SPIL scheme provides for robust measurement of CBF with multi-slice imaging capability.
  • the present invention relates to an ASL scheme called steady pulsed imaging and labeling (SPIL).
  • SPIL steady pulsed imaging and labeling
  • the new SPIL scheme borrows a principle applied in pulsed magnetization transfer (MT) and pulsed chemical exchange saturation transfer (CEST) studies, such as VDMP-CEST and FLEX. Both ASL and MT/CEST evaluate exchange processes.
  • MT pulsed magnetization transfer
  • CEST pulsed chemical exchange saturation transfer
  • VDMP-CEST pulsed chemical exchange saturation transfer
  • Both ASL and MT/CEST evaluate exchange processes.
  • ASL during the exchange process, the label bolus enters the microvasculature and exchanges with tissue water in the imaging slice, while in CEST, water-exchangeable protons are labeled and exchange with the large water pool.
  • the ASL signal can be easily contaminated by MT effects; some techniques that have been applied in ASL studies to suppress MT effects also have been implemented in the CEST field, such as amplitude modulated CASL and double-saturation CEST.
  • CASL CASL
  • pTILT pseudo-continuous transfer-insensitive labeling technique
  • PCASL PCASL
  • the new approach of Steady Pulsed Imaging and Labeling repeats a labeling-exchange module (LEM), nomenclature similar to the FLEX approach consisting of an un-inverted flow-sensitive alternating inversion recovery (UNFAIR) labeling followed by a mixing time.
  • LEM labeling-exchange module
  • NDFAIR un-inverted flow-sensitive alternating inversion recovery
  • the multi-slice images in SPIL are acquired interleaved with the label units.
  • the mixing time after the UNFAIR module i.e. the bolus duration, is also used for magnetization recovery following multi-slice image acquisition.
  • the SPIL module consists of repeated units of a labeling scheme followed by a mixing time and is repeated interleaved with imaging.
  • the UNFAIR scheme is applied for labeling, as shown in FIG. 1A.
  • FIG. 1A illustrates a graphical view of the SPIL sequence composed of a series of labeling and exchange modules (LEMs), each containing two adiabatic inversion pulses, and followed by a mixing time (tmix) to enable the labeled water spins to perfuse into the tissue in the image slice.
  • LEMs labeling and exchange modules
  • tmix mixing time
  • Perfusion images are obtained by subtraction of the labeling images from the control images.
  • the water spins in the whole mouse brain are inverted twice in one labeling module by a pair of non-selective 180° inversion pulses.
  • the labeling of the blood water spins is performed by non-selective inversion of the whole brain, followed by selective inversion of the imaging slice. Therefore, the water spins outside the imaging slice are inverted.
  • a waiting period, t m ix is applied to allow labeled spins to perfuse into the tissues of the imaging slice. Due to repetition of the
  • the mixing time in the LEM is used for magnetization recovery and contributes to the bolus duration time.
  • the bolus duration ⁇ is the time period that the labeled arterial blood flowing into the imaging slices.
  • the major factor determining ⁇ of one LEM is coil coverage.
  • the excitation coil covers the majority of the mouse body. Therefore, the bolus duration for one LEM is far longer than the mixing time.
  • the ratio of the bolus duration time to the repetition time (TR) is labelled as the labeling duty cycle.
  • the labeling duty cycle is 100%, while it is around 32% for the PCASL method.
  • the final perfusion signal is a combined effect between the label efficiency and the labeling duty cycle.
  • the second selective inversion slice is wider than the imaging slice, in order to ensure that the imaging slice is completely inverted.
  • the gap between the imaging slice and the inversion slice is called a slab margin, illustrated in FIG. IB.
  • FIG. IB illustrates a schematic diagram of the inversion slab positions, with respect to the image slice.
  • a 180° hyperbolic secant (sech) pulse was applied as a selective inversion pulse, and its offset was set to the center of the imaging slice package. Therefore, the offsets of each of the slice selection pulses varied significantly with respect to the offset of the inversion pulse.
  • the pulse profile of the inversion pulses was critical for obtaining perfusion images without contamination, especially for the slices far away from the center of the slice package.
  • the perfusion kinetic curve i.e., the perfusion signal with respect to the total label duration, is needed to obtain the parameters required for absolute quantification of CBF, and was obtained here by observing the single-slice ASL signal before reaching steady-state in the SPIL sequence.
  • the single-slice non-steady-state SPIL sequence is referred to as multi- pulsed imaging and labeling (MPIL) and is illustrated in FIGS. 1C and ID.
  • FIG. 1C illustrates a graphical view of a time diagram of the MPIL scheme.
  • FIG. ID illustrates a schematic diagram of the inversion slab positions, with respect to the image slices, for the MPIL sequence.
  • the labeling duration in MPIL is defined by the start of the first LEM until the imaging readout, and is analogous to the labeling duration in CASL/PCASL.
  • the variation of label duration is achieved by increasing mixing time in the LEMs, while keeping the number of LEMs constant.
  • FIG. IE illustrates a graphical view of the steady velocity selective pulsed imaging (SVASL) and labeling sequence composed of a series of velocity selective labeling and exchange modules, each containing two 90 degree pulses with two 180 degree refocus pulse in between, and the velocity selective unit followed by a mixing time (tmb.) to enable the labeled water spins to perfuse into the tissue in the image slice.
  • FIG. IF illustrates the multi-pulsed velocity selective imaging and labeling sequence (MVASL).
  • a standard ASL single-compartment kinetic model was applied to quantity CBF, assuming instantaneous exchange of labeled spins from capillary to tissue.
  • the observed ASL signal is described by the difference between the sum over the series of delivered magnetization units to the tissue (the arterial input function, AIF), and the clearance of the magnetization by venous flow and relaxation of the blood (the impulse residue function, IRF).
  • the description of the AIF function for SPIL is complicated because the labeled blood from the first label transfer module will be inverted several times by the subsequent labeling and a steady state for labeling and T i relaxation is generated.
  • a is the labeling efficiency of one LEM
  • ⁇ is the blood-brain partition coefficient
  • Mo is the equilibrium magnetization of arterial blood
  • relaxation time of arterial blood f is the CBF in units of volume of blood delivered per weight of tissue per unit time (ml/g/s)
  • ATT is the arterial transit time.
  • the labeling efficiency, a reaches unity if the inversion pulses are perfect, while it is 0.5 if the pulses are saturation pulses, i.e., 90-degree pulses followed by dephasing.
  • the signal intensity of the control images is assumed to be equal to Mo in the above discussion.
  • the attenuation factor, ⁇ describes the signal reduction due to the signal loss by one labeling module.
  • MR Scanning All MRI experiments were performed on a horizontal bore 11.7 T Bruker Biospec system (Bruker, Ettlingen, Germany). A 72 mm quadrature volume resonator was used as transmitter, and two sets of receiver coils were used for the current study. A 2x2 mouse phased array coil was used for the adult mouse study, and a 10 mm planar surface coil was used for the P 10 mouse study. All coils were provided by Bruker Corporation (Ettlingen, Germany).
  • the matrix size was reduced to 48 x 48 to acquire the perfusion kinetic curves.
  • a 13 ms sech pulse (6 kHz bandwidth) were used for the inversion pulses.
  • ASL Arterial spin labeling
  • MTC magnetization transfer contrast
  • This experiment was designed to demonstrate multi-slice perfusion image quality obtained using SPIL.
  • Five slices or ten slices with slice thickness 1mm were acquired in each mouse brain.
  • the slab margin was set to 6 mm, and the total inversion slab thickness was 19 mm.
  • the total acquisition time was 8 minutes with the number of averages (NAV) 8, and the mixing time was 1 s for five slices, while 2 s for ten slices.
  • NAV number of averages
  • This experiment was designed to demonstrate that SPIL performs well on mice with small body size, and is able to detect unilateral reductions in brain perfusion.
  • the labeling efficiency (a) was set to 0.9, and the blood-brain partition coefficient ( ⁇ ) was assumed to be 0.9 mL/g.
  • FIGS. 2A and 2B illustrate graphical views of the arterial input function (AIF) and the corresponding perfusion signal ( ⁇ / ⁇ ) for the SPIL scheme, respectively.
  • the bolus duration of the UNFAIR labeling module was assumed to be 6 s.
  • the relaxation time of arterial blood is assumed to be 2.8 s.
  • the labeling efficiency was set to
  • FIGS. 2C and 2D illustrate a graphical view of the typical AIF for MPIL with the parameters used in FIGS. 2A and 2B.
  • the corresponding time course of the MPIL sequence with four LEMs is plotted on the top of the figure.
  • FIG. 2D illustrates a graphical view of the simulated perfusion kinetic curves for the single slice SPIL with 1, 2, and 4 label modules, respectively.
  • the MPIL sequence is the UNFAIR sequence.
  • the perfusion signal built up initially, with respect to the total label duration, and then decayed slowly due to the effective relaxation time Ti, e s.
  • the maximum perfusion signal recorded using one, two, and four labeling modules is comparable, as demonstrated in FIG. 2D.
  • FIGS. 3A-3B illustrate the SPIL perfusion signal from several slices over a postmortem mouse brain with two different slab margins, 2 mm and 6 mm.
  • FIG. 3A illustrates control images (Mcontroi) from a post mortem mouse brain. Only three slices located at -3 mm, 0 mm, and 3mm from the isocenter of the magnet are shown as examples.
  • FIGS. 3B and 3C illustrate difference images (AM/M CO ntroi) recorded using the SPIL scheme, with slab margins of 2 mm in FIG. 3B and 6 mm in FIG. 3C.
  • the perfusion signal measured at the center slice of the brain was less than 0.2 % (averaged over the brain) of the control images.
  • This contamination of the perfusion signal was mainly attributable to the imperfect inversion profile of the sech inversion pules when offsets were far from the center frequency.
  • the contamination could be suppressed significantly by increasing the slab margin to 6 mm, where a whole-brain average signal less than 0.2 % of the control value was observed for the slices 3 mm from the isocenter (see FIG. 3C). Therefore, a slab margin of 6 mm was used for all the SPIL studies reported here.
  • FIGS. 4A-4E illustrate image and graphical views showing normalized difference images ( ⁇ /Mcontroi) from a healthy mouse brain with different crusher gradient strengths.
  • FIG. 4A the crush gradient is 4.77 cm/s.
  • FIG. 4B the crush gradient is 11.3 mT/m.
  • FIG. 4C the crush gradient is 27.8 mT/m.
  • FIG. 4D illustrates an image recorded using the SPIL sequence.
  • FIG. 4E illustrates the control image and the ROIs for the cortex (dark grey arrow) and artery (light grey arrow) perfusion signal. The perfusion signal with respect to the crusher gradients for the cortex and artery.
  • the crusher gradients are triangle- shaped with ramp time 0.59 ms; the separation between two crusher gradients is 2.4 ms. It can be seen that signals from arterial blood, such as the middle cerebral artery (MCA) and the superficial temporal artery/vein, decreased significantly with higher crusher gradients. The maximum crusher gradient is limited by the gradient slew rate of the MRI system. Also, high crusher gradients can cause image artifacts due to eddy currents, reducing image quality. In the experiments, a crusher gradient of 27.8 mT/m was able to suppress the arterial blood in adult mice, while the perfusion signal from cortex did not show noticeable decrease when cruehsr gradient strength was increased by five times. This indicates that the intra-arterial spin signal is already intrinsically suppressed by the FSE readout.
  • FIGS. 5A and 5B illustrate graphical views of experimental perfusion kinetic curves, with respect to the total label time.
  • FIG. 5A illustrates data recorded for the MPIL sequence with one LEM, i.e., the UNFAIR sequence, and four LEMs in FIG. 5B. Data were measured in healthy adult mouse brains.
  • the label duration was assumed to be 6 s. A 5 s pre-scan delay was used. Similar to the simulation (FIG. 2D), the perfusion kinetic curve for one labeling module (UNFAIR) reached a peak at 1.8 s (3.5 % control) and then decayed with From the kinetic curves (FIG. 5 A), it can be seen that the bolus duration of one UNFAIR module is longer than 4 s, i.e., the maximum label time. Any bolus duration longer than 4 s will not change the curves. Therefore, a bolus duration of 6 s was used for fitting. The blood in the whole mouse body was labeled by the 72 mm coil, which led to extremely long bolus durations.
  • FIGS. 6A and 6B illustrate images of typical multi-slice ASL images of the mouse brain obtained with the SPIL scheme for a five and ten slices, respectively, with a resolution of 250x250 ⁇ 2 -.
  • Five slices (FIG. 6A) and ten slices (FIG. 6B) with a slice thickness of 1 mm were acquired.
  • the mixing time was 1 s and 2 s for five slices and ten slices, respectively.
  • a single slice acquisition was performed during the exchanging time (FIG. 6A), while four slices were recorded for the ten slices situation (FIG. 6B).
  • the Mcontrol images are shown above the perfusion images for comparison (top row).
  • the blood vessel suppression method applied in this study i.e., vascular crusher gradients in one direction, was unable to suppress the PCA signal completely.
  • FIG. 7 illustrates a graphical view of Bilateral symmetry of CBF for three brain regions in five mice: cortex (triangle), hippocampus (circle), and thalamus (diamond). Error bars represent the in-ROI standard derivations. Typical ROIs for the three brain regions are illustrated in the figure inset. The CBF difference is less than 10% for the three brain structures. The CBF values from cortex show slightly bigger differences, which may be due to head motion. The within-ROI standard deviations were also plotted in the same figure, and were found to be around 15% of the mean CBF values.
  • FIGS. 8A and 8B Typical perfusion images of immature (PI 1) mouse brain undergoing unilateral ischemia obtained using SPIL are shown in FIGS. 8A and 8B. Typical T2 -weighted images are also presented for comparison.
  • FIG. 8B illustrates representative multi-slice perfusion maps (bottom row) on postnatal mouse brain with a stroke model, acquired using the SPIL scheme.
  • FIG. 9 illustrates perfusion images of mouse brain recorded on mouse with 9L- gliomas. 200,000 cells (in 2uL) were injected to induce glioma, and the images were recorded one week after injection.
  • the glioma regions show hypointense perfusion.
  • FIGS. lOA-lOC illustrates a High-resolution perfusion, T2w, T iw and Apparent
  • FIG. 10A illustrates T2 weigthed images recorded using a RARE MRI pulse sequence with TE 30 ms.
  • FIG. 10B illustrates a perfusion image acquired using SPIL sequence with 10 slices and in-plane resolution of 250 ⁇ .
  • FIG. IOC illustrates an Apparent Diffusion Coefficient (ADC) map was acquried using DTI-EPI sequence with 4 diffusion direction and B value of 830 s/mm 2 .
  • the ischemia was introduced by the middle cerebral artery occlusion (MCAO). MRI scans were performed 6 hours after the surgery.
  • the perfusion map shows strong hypointense on the ipsilateral hemisphere of the brain.
  • a new ASL scheme, dubbed SPIL, is included to obtain mouse brain perfusion images.
  • the new method has several unique advantages for performing multi-slice perfusion imaging besides the typical advantages of PASL methods (i.e., no MT background interference, low SAR, and easy implementation): (i) The new scheme is robust to experimental errors and in the quantification of CBF; (ii) the experimental time is short for multi-slice perfusion imaging; (iii) multi-slice perfusion images recorded by SPIL method do not require correction for the post-label time for each slice.
  • the SPIL scheme closely resembles a standard FSE sequence, except that one label unit is applied after each acquisition period. Therefore, the total experimental time is twice that of the FSE sequence.
  • the bolus duration can be treated as infinite for each imaging slice.
  • the new scheme eliminates the pre-scan delay and labeling time. Notice the pre-scan delay and labeling time are still necessary in MPIL sequence.
  • the label efficiency (around 0.5) of SPIL is lower than that of typical PCASL methods (around 0.7-0.8)
  • the higher labeling duty cycle (100%) enables SPIL to obtain perfusion images faster than traditional methods (labeling duty cycle between 30-40%) with similar perfusion image SNR. This advantage is significant when performing multi-slice perfusion imaging, since the total experimental time does not increase with more slices.
  • the enhancement factor of SPIL is defined by the ratio of the perfusion signal recorded by SPIL to that obtained using a single LEM, i.e., UNFAIR in the current study.
  • the enhancement factor is determined by the bolus duration of the single LEM. When the bolus duration is short, the enhancement by SPIL is high since the method can extend the bolus duration significantly; the enhancement factor is around 2.5 when bolus duration is 1 s.
  • the signal enhancement of SPIL scheme is limited for extremely long bolus durations; the enhancement factor is 1.2 with bolus duration of 6 s, as is the case in the study. Using a long bolus duration, the perfusion signal already reaches steady state and will not gain
  • the high multi- slice perfusion signal intensity of SPIL was achieved by eliminating the separate label time commonly applied in PASL and CASL sequences.
  • Multi-slice perfusion-weighted images obtained by conventional PASL and CASL methods are acquired from the first slice to the n-th slice, with no inter-image delay after the perfusion labeling period.
  • the perfusion signal intensity will decrease from the first slice to the n-th slice due to the increased post-label delay with respect to the slice acquisition order. This complicates whole-brain CBF quantification, since it is challenging to model this signal decrease. This also limits the spatial resolution and the spatial coverage (i.e., number of slices).
  • the multi-slice SPIL perfusion acquisition method is an elegant solution to this problem.
  • the slice acquisition distributes uniformly over the total label period. Therefore, each slice has exactly the same steady-state labeling efficiency and post-label delay; slice-wise corrections to CBF are unnecessary.
  • the new scheme was demonstrated on a preclinical MRI scanner, it appears well-suited for human scanners, especially 7T MRI scanners, where SAR and BO/Bl inhomogeneity are serious issues for pCASL and CASL methods, transmit homogeneity is poor and the transmit coils often too short for labeling of the neck.
  • the blood signal was saturated by continuous application of UNFAIR labeling modules.
  • Other labeling modules can replace the UNFAIR module, such as the transfer-insensitive labeling technique (TILT).
  • TILT scheme slightly reduces saturation efficiency compared to the UNFAIR labeling module; however, SAR will be reduced by 75% if 90-degree pulses are applied, which is potentially important for 7 T human scanners.
  • the SAR of the two sequences can be further reduced by changing from FSE to other image acquisition methods such as GRASE, FLASH, or EPI.
  • SPIL long labeling time in SPIL not only allows time-efficient acquisition of perfusion images, but, unfortunately, also enhances vascular artifacts.
  • crusher gradients in the FSE readout partially solved the problem.
  • a new ASL scheme is presented herein and is referred to as, SPIL, to quantify CBF in vivo in the mouse brain.
  • the new scheme can improve the time efficiency and bolus duration by making use of the principle of interleaving image acquisitions and label transfer modules.
  • SPIL offers high sensitivity and high-quality multi-slice perfusion images from both adult and immature mouse brains.
  • the new SPIL scheme would be advantageous in preclinical application of ASL, which requires robust and accurate quantitative measurements of CBF.
  • Such non-transitory computer readable media includes, but is not limited to, magnetic media, such as a floppy disk, flexible disk, hard disk, reel-to-reel tape, cartridge tape, cassette tape or cards, optical media such as CD-ROM, writable compact disc, magneto-optical media in disc, tape or card form, and paper media, such as punched cards and paper tape.
  • the computing device can be a special computer designed specifically for this purpose.
  • the computing device can be unique to the present invention and designed specifically to carry out the method of the present invention. All MRI systems have a console which is a proprietary master control center of the MRI system designed specifically to carry out the operations of the system and receive the imaging data created by the system.
  • this console is made up of a specialized computer, custom keyboard, and multiple monitors.
  • control consoles There can be two different types of control consoles, one used by the MRI operator and the other used by the physician.
  • the physician's viewing console allows viewing of the images without interfering with the normal operation.
  • This console is capable of rudimentary image analysis.
  • the operating console computer is a non- generic computer specifically designed by the manufacturer for bilateral (input output) communication with the system. It is not a standard business or personal computer that can be purchased at a local store. Additionally this console computer carries out communications with the scanner through the execution of proprietary custom built software that is designed and written by the scanner manufacturer for the computer hardware to specifically operate the system hardware.

Landscapes

  • Health & Medical Sciences (AREA)
  • Physics & Mathematics (AREA)
  • Nuclear Medicine, Radiotherapy & Molecular Imaging (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • General Health & Medical Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Cardiology (AREA)
  • Biophysics (AREA)
  • High Energy & Nuclear Physics (AREA)
  • Condensed Matter Physics & Semiconductors (AREA)
  • General Physics & Mathematics (AREA)
  • Hematology (AREA)
  • Radiology & Medical Imaging (AREA)
  • Physiology (AREA)
  • Vascular Medicine (AREA)
  • Signal Processing (AREA)
  • Pathology (AREA)
  • Biomedical Technology (AREA)
  • Heart & Thoracic Surgery (AREA)
  • Medical Informatics (AREA)
  • Molecular Biology (AREA)
  • Surgery (AREA)
  • Animal Behavior & Ethology (AREA)
  • Public Health (AREA)
  • Veterinary Medicine (AREA)
  • Magnetic Resonance Imaging Apparatus (AREA)

Abstract

La présente invention concerne un procédé d'imagerie et de marquage stationnaire (SPIL) pour obtenir des images de perfusion multi-coupes à haute résolution de cerveau en utilisant un équipement IRM clinique standard. Le schéma SPIL répète un module de marquage de spin artériel pulsé (PASL) conjointement avec un temps de mélange court pour prolonger la durée temporelle du bolus PASL généré au temps expérimental total. L'acquisition d'images multi-coupes est entrelacée avec les modules de marquage. Le temps de mélange est également utilisé pour récupération de magnétisation après acquisition d'image. SPIL produit des images de perfusion multi-coupes plus rapidement que les procédés ASL conventionnels. La courbe de cinétique de perfusion peut être mesurée par MPIL, c'est-à-dire l'acquisition d'un signal ASL mono-coupe avant d'atteindre l'état stationnaire dans la séquence SPIL. Le nouveau schéma SPIL permet la mesure robuste de CBF avec capacité d'imagerie multi-coupes.
PCT/US2015/061460 2014-11-19 2015-11-19 Schéma d'imagerie et de marquage pulsé stationnaire pour perfusion non invasive WO2016081677A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US201462081624P 2014-11-19 2014-11-19
US62/081,624 2014-11-19

Publications (1)

Publication Number Publication Date
WO2016081677A1 true WO2016081677A1 (fr) 2016-05-26

Family

ID=56014541

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/US2015/061460 WO2016081677A1 (fr) 2014-11-19 2015-11-19 Schéma d'imagerie et de marquage pulsé stationnaire pour perfusion non invasive

Country Status (1)

Country Link
WO (1) WO2016081677A1 (fr)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN106405459A (zh) * 2016-08-24 2017-02-15 沈阳东软医疗系统有限公司 一种时间校正方法、装置及设备
RU2702587C1 (ru) * 2018-11-08 2019-10-08 Федеральное государственное бюджетное научное учреждение "Научный центр неврологии" (ФГБНУ НЦН) Способ оценки скорости церебрального кровотока в зонах нейрональной активации
CN116879338A (zh) * 2023-06-12 2023-10-13 汕头大学医学院第二附属医院 一种vdmp-cest结合非线性拟合检测gaba的方法及系统

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5054489A (en) * 1988-10-06 1991-10-08 The Trustees Of The University Of Pennsylvania Magnetic resonance imaging using spatial modulation of magnetization
EP0270320B1 (fr) * 1986-12-03 1992-09-23 Advanced Nmr Systems Inc. Méthode d'imagerie rapide par résonance magnétique nucléaire
US5275163A (en) * 1991-04-02 1994-01-04 U.S. Philips Corporation Magnetic resonance imaging method and device for monitoring motion of a part of an object
JP2004242948A (ja) * 2003-02-14 2004-09-02 Toshiba Corp Ｍｒｉ装置及びａｓｌイメージング方法
WO2014151596A2 (fr) * 2013-03-15 2014-09-25 Beth Israel Deaconess Medical Center Système et procédé pour imagerie par résonance magnétique à transfert d'aimantation inhomogène

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0270320B1 (fr) * 1986-12-03 1992-09-23 Advanced Nmr Systems Inc. Méthode d'imagerie rapide par résonance magnétique nucléaire
US5054489A (en) * 1988-10-06 1991-10-08 The Trustees Of The University Of Pennsylvania Magnetic resonance imaging using spatial modulation of magnetization
US5275163A (en) * 1991-04-02 1994-01-04 U.S. Philips Corporation Magnetic resonance imaging method and device for monitoring motion of a part of an object
JP2004242948A (ja) * 2003-02-14 2004-09-02 Toshiba Corp Ｍｒｉ装置及びａｓｌイメージング方法
WO2014151596A2 (fr) * 2013-03-15 2014-09-25 Beth Israel Deaconess Medical Center Système et procédé pour imagerie par résonance magnétique à transfert d'aimantation inhomogène

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN106405459A (zh) * 2016-08-24 2017-02-15 沈阳东软医疗系统有限公司 一种时间校正方法、装置及设备
CN106405459B (zh) * 2016-08-24 2019-10-18 东软医疗系统股份有限公司 一种时间校正方法、装置及设备
US10830858B2 (en) 2016-08-24 2020-11-10 Shanghai Neusoft Medical Technology Co., Ltd. Correcting time
RU2702587C1 (ru) * 2018-11-08 2019-10-08 Федеральное государственное бюджетное научное учреждение "Научный центр неврологии" (ФГБНУ НЦН) Способ оценки скорости церебрального кровотока в зонах нейрональной активации
CN116879338A (zh) * 2023-06-12 2023-10-13 汕头大学医学院第二附属医院 一种vdmp-cest结合非线性拟合检测gaba的方法及系统

Similar Documents

Publication Publication Date Title
JP6786670B2 (ja) 磁気共鳴イメージング装置
JP2926110B2 (ja) 傾斜およびスピンエコー（ｇｒａｓｅ）イメージングを用いた超高速多重セクション全身ｍｒｉ
Fan et al. Carotid arterial wall MRI at 3T using 3D variable‐flip‐angle turbo spin‐echo (TSE) with flow‐sensitive dephasing (FSD)
Lewin et al. Three-dimensional time-of-flight MR angiography: applications in the abdomen and thorax.
Fernández‐Seara et al. Minimizing acquisition time of arterial spin labeling at 3T
Neggers et al. Enhanced sensitivity with fast three‐dimensional blood‐oxygen‐level‐dependent functional MRI: comparison of SENSE–PRESTO and 2D‐EPI at 3 T
US7627359B2 (en) Quantitative contrast enhanced black-blood imaging using quadruple-inversion recovery
Fitts et al. Arrhythmia insensitive rapid cardiac T1 mapping pulse sequence
Li et al. Theoretical and experimental evaluation of multi-band EPI for high-resolution whole brain pCASL Imaging
Schmid et al. Acceleration‐selective arterial spin labeling
US20160113501A1 (en) Functional Magnetic Resonance Imaging (fMRI) Methodology Using Transverse Relaxation Preparation and Non-Echo-Planar Imaging (EPI) Pulse Sequences
US9911206B2 (en) Time efficient ASL imaging with segmented multiband acquisition
US20050030024A1 (en) Methods for multiple acquisitions with global inversion cycling for vascular-space-occupancy dependant and apparatuses and devices related thereto
de Boer et al. 7 T renal MRI: challenges and promises
US10330762B2 (en) Measurement of blood volume using velocity-selective pulse trains on MRI
Park et al. Physiological and functional magnetic resonance imaging using balanced steady-state free precession
Shimizu et al. Arterial transit time-corrected renal blood flow measurement with pulsed continuous arterial spin labeling MR imaging
WO2016081677A1 (fr) Schéma d'imagerie et de marquage pulsé stationnaire pour perfusion non invasive
US7368910B2 (en) Dual gradient echo pulse sequence using interleaved spiral-out spiral-in k-space trajectories
Xu et al. Steady pulsed imaging and labeling scheme for noninvasive perfusion imaging
Brown et al. Effect of blood flow on double inversion recovery vessel wall MRI of the peripheral arteries: Quantitation with T2 mapping and comparison with flow‐insensitive T2‐prepared inversion recovery imaging
JPH11299753A (ja) Ｍｒｉ装置およびｍｒ撮像方法
US9009016B2 (en) NMR measurement of contrast medium concentrations
US20210228096A1 (en) Measurement of blood volume using fourier-transform based velocity-selective pulse trains on mri
Ouyang et al. Pseudo‐continuous transfer insensitive labeling technique

Legal Events

Date Code Title Description
121 Ep: the epo has been informed by wipo that ep was designated in this application

Ref document number: 15860611

Country of ref document: EP

Kind code of ref document: A1

NENP Non-entry into the national phase

Ref country code: DE

122 Ep: pct application non-entry in european phase

Ref document number: 15860611

Country of ref document: EP

Kind code of ref document: A1