WO2004090565A1 - Magnetic resonance imaging with histogram-based phase correction - Google Patents
Magnetic resonance imaging with histogram-based phase correction Download PDFInfo
- Publication number
- WO2004090565A1 WO2004090565A1 PCT/IB2004/050394 IB2004050394W WO2004090565A1 WO 2004090565 A1 WO2004090565 A1 WO 2004090565A1 IB 2004050394 W IB2004050394 W IB 2004050394W WO 2004090565 A1 WO2004090565 A1 WO 2004090565A1
- Authority
- WO
- WIPO (PCT)
- Prior art keywords
- magnetic resonance
- phase correction
- phase
- histogram
- resonance imaging
- Prior art date
Links
Classifications
-
- 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
- G01R33/565—Correction of image distortions, e.g. due to magnetic field inhomogeneities
Definitions
- the invention pertains to a magnetic resonance imaging system which involves correction of phase values of the magnetic resonance image.
- Magnetic resonance imaging with phase correction is known from the paper new phase correction method in NMR imaging based on autocorrelation and histogram analysi ' by C.B. Ahn and Z.H. Cho in IEEE Trans.MI 6(1987)32-36.
- the known magnetic resonance imaging proposes to correct the phase of the complex valued pixels by first making an estimate of the first order phase error.
- This first order phase error is the contribution to the phase error in a complex valued pixel that is linearly dependent on the position of the pixel in the complex image.
- This first order phase error is calculated from the autocorrelation between adjacent pixels.
- a first-order phase error corrected image is derived.
- a histogram of phase values of the first-order phase error corrected image is formed. From the location of one peak in this histogram or of peaks being separated by 180° in this histogram, the zero -order phase error is estimated.
- This zero -order phase error is the overall contribution that is independent of the position of the position of the pixel in the complex image.
- An object of the invention is to provided an magnetic resonance imaging method in which phase errors having a complicated nature are corrected more accurately.
- a magnetic resonance imaging method comprising a reconstruction unit arranged to reconstruct a complex image of complex valued pixels from magnetic resonance signals compute a distribution of phase values of the complex image apply a phase correction to the complex image to form a corrected magnetic resonance image and control the phase correction on the basis of the distribution of phase values of the complex image.
- the phase correction is controlled on the basis of the distribution of the phase values of the complex image. It appears that the distribution of phase values is quite sensitive for the way the phase error depends on the position in the complex valued image. Consequently, the distribution of phase values is an accurate indicator for the kind of phase corrections to be effective and also for the accuracy of the result achieved by the phase correction actually applied.
- the distribution of phase values in the complex image is represented by a histogram of phase values.
- Generation of the histogram from the complex values of the pixels of the complex image requires very low computational effort and takes only a small memory capacity.
- the features of the histogram appear to be very sensitive to the way the phase error varies over the complex valued image.
- the features of the histogram also accurately indicate the accuracy achieved in correction of the phase error.
- the use of test functions applied to the histogram enhances the sensitivity for particular patterns of variation of the phase error over the complex valued image. Further, the test function provides an easy indication of the accuracy of the correction in terms of a simple real valued number.
- test functions are chosen from the class of functions /that satisfy: f(h) ⁇ h (h ⁇ I) .
- These test functions enhance peaks in the histograms relative to broader structures. Accurate correction of the phase errors leads to peaks in the histogram and removes broad structures.
- these test functions provide an accurate indication of the accuracy of the correction of the phase errors.
- Particularly good results are obtained when the histogram power function is employed as the test function.
- the histogram power function is defined as P(H) — h .
- H denotes the histogram and h j is the number of phase-
- the histogram power function strongly emphasises histograms having a few strong peaks and returns low values for histograms having mainly broad features. Thus the histogram power function provides an effective test which indicates if the phase correction is accurate.
- polynomial phase corrections are carried-out.
- Such polynomial phase corrections require low computational effort and require only a short computation time. Accordingly, several polynomial phase corrections can be tried within a short time and for the respective phase corrections the histogram is constructed and the histogram power function is computed. Then, the most effective correction is selected on the basis of the minimum histogram power function value.
- the respective polynomial phase corrections are easily effected just by adapting the polynomial coefficients of the polynomial phase corrections and re-iterating the phase correction with the adjusted polynomial coefficients.
- the polynomial coefficients are adjusted so as to optimise the value of the test function of the histogram.
- phase correction is adjusted by resetting the polynomial coefficients on the basis of a trial and improve algorithm so arrive at a set of polynomial coefficients that correspond to a phase distribution of which the test function of the histogram has it optimum value, notably the histogram power function, is minimum.
- the corrected magnetic resonance image is practically void of artefacts caused by phase errors in the magnetic resonance signals. Accordingly, the corrected magnetic resonance image has a high diagnostic value in that the anatomy of the patient to be examined is imaged faithfully, even for small details with low contrast or low contrast- resolution.
- the invention also relates to a magnetic resonance imaging method as defined in Claim 10.
- the magnetic resonance imaging method of the invention achieves accurate correction of phase errors in the complex valued image.
- the invention further relates to a computer programme as defined in Claim 11.
- the computer programme of the invention can be loaded into the reconstruction unit of the magnetic resonance imaging system. Accordingly the reconstruction unit is able to perform accurate correction of phase errors in the complex valued image that is reconstructed from the magnetic resonance signals generated by the magnetic resonance imaging system.
- Figure 1 shows a flow chart of an implementation of the method of the invention
- Figure 2 shows a schematic representation of a magnetic resonance imaging system in which the invention is employed.
- FIG. 1 shows a flow chart of an implementation of the method of the invention.
- the magnetic resonance imaging method of the invention involves acquisition (mr-acq)of magnetic resonance signals. From the acquired magnetic resonance signals, the complex image is reconstructed (Im-recon). For individual complex valued pixels of the complex image, the phase is computed. Then the phase-values for the pixels are binned into th histogram. That is, phase- values in pre-determined phase-intervals, the bins, are counted and the numbers of phase values in respective bins form the histogram H.
- a polynomial phase correction is selected and applied to the current complex image.
- the histogram power function has its minimum value which indicates that the histogram contains a few strong peaks which indicates that the current phase correction is adequate.
- a final phase correction can be performed on the basis of the histogram having the minimum histogram power function value.
- the optional final phase correction may involve an accurate water-fat shift correction.
- FIG. 2 shows a schematic representation of a magnetic resonance imaging system in which the invention is employed.
- the magnetic resonance imaging system includes a set of main coils 10 whereby the steady, uniform magnetic field is generated.
- the main coils are constructed, for example in such a manner that they enclose a tunnel-shaped examination space. The patient to be examined is slid into this tunnel-shaped examination space.
- the magnetic resonance imaging system also includes a number of gradient coils 11, 12 whereby magnetic fields exhibiting spatial variations, notably in the form of temporary gradients in individual directions, are generated so as to be superposed on the uniform magnetic field.
- the gradient coils 11, 12 are connected to a controllable power supply unit 21.
- the gradient coils 11, 12 are energised by application of an electric current by means of the power supply unit 21. The strength, direction and duration of the gradients are controlled by control of the power supply unit.
- the magnetic resonance imaging system also includes transmission and receiving coils 13, 16 for generating the RF excitation pulses and for picking up the magnetic resonance signals, respectively.
- the transmission coil 13 is preferably constructed as a body coil 13 whereby (a part of) the object to be examined can be enclosed.
- the body coil is usually arranged in the magnetic resonance imaging system in such a manner that the patient 30 to be examined is enclosed by the body coil 13 when he or she is arranged in the magnetic resonance imaging system.
- the body coil 13 acts as a transmission antenna for the transmission of the RF excitation pulses and RF refocusing pulses.
- the body coil 13 involves a spatially uniform intensity distribution of the transmitted RF pulses (RFS).
- the same coil or antenna is usually used alternately as the transmission coil and the receiving coil.
- the transmission and receiving coil is usually shaped as a coil, but other geometries where the transmission and receiving coil acts as a transmission and receiving antenna for RF electromagnetic signals are also feasible.
- the transmission and receiving coil 13 is connected to an electronic transmission and receiving circuit 15.
- receiving coils 16 can be used as receiving coils. Such surface coils have a high sensitivity in a comparatively small volume.
- the transmission coils such as the surface coils, are connected to a demodulator 24 and the received magnetic resonance signals (MS) are demodulated by means of the demodulator 24.
- the demodulated magnetic resonance signals (DMS) are applied to a reconstruction unit.
- the receiving coil is connected to a preamplifier 23.
- the preamplifier 23 amplifies the RF resonance signal (MS) received by the receiving coil 16 and the amplified RF resonance signal is applied to a demodulator 24.
- the demodulator 24 demodulates the amplified RF resonance signal.
- the demodulated resonance signal contains the actual information concerning the local spin densities in the part of the object to be imaged.
- the transmission and receiving circuit 15 is connected to a modulator 22.
- the modulator 22 and the transmission and receiving circuit 15 activate the transmission coil 13 so as to transmit the RF excitation and refocusing pulses.
- the reconstruction unit derives one or more image signals from the demodulated magnetic resonance signals (DMS), which image signals represent the image information of the imaged part of the object to be examined.
- the reconstruction unit 25 in practice is constructed preferably as a digital image processing unit 25 which is programmed so as to derive from the demodulated magnetic resonance signals the image signals which represent the image information of the part of the object to be imaged.
- the reconstruction unit of the magnetic resonance imaging system according to the invention is also provided with a processing unit, for example in the form of a computer which includes a (micro)processor.
- the processing unit of the reconstruction unit is arranged to carry out the phase correction to the complex valued image on the basis of the distribution of phase values in the complex valued image, e.g. as represented by the histogram
- the computer program according to the invention is loaded, for example, into the processing unit of the reconstruction unit 25.
Landscapes
- Physics & Mathematics (AREA)
- Health & Medical Sciences (AREA)
- General Health & Medical Sciences (AREA)
- Nuclear Medicine, Radiotherapy & Molecular Imaging (AREA)
- Radiology & Medical Imaging (AREA)
- Engineering & Computer Science (AREA)
- Signal Processing (AREA)
- High Energy & Nuclear Physics (AREA)
- Condensed Matter Physics & Semiconductors (AREA)
- General Physics & Mathematics (AREA)
- Magnetic Resonance Imaging Apparatus (AREA)
Abstract
Description
Claims
Priority Applications (3)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
EP04725774A EP1623246A1 (en) | 2003-04-14 | 2004-04-05 | Magnetic resonance imaging with histogram-based phase correction |
JP2006506814A JP2006522638A (en) | 2003-04-14 | 2004-04-05 | Magnetic resonance imaging using histogram-based phase correction |
US10/553,327 US7301340B2 (en) | 2003-04-14 | 2004-04-05 | Magnetic resonance imaging with histogram-based phase correction |
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
EP03100997.0 | 2003-04-14 | ||
EP03100997 | 2003-04-14 |
Publications (1)
Publication Number | Publication Date |
---|---|
WO2004090565A1 true WO2004090565A1 (en) | 2004-10-21 |
Family
ID=33155243
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
PCT/IB2004/050394 WO2004090565A1 (en) | 2003-04-14 | 2004-04-05 | Magnetic resonance imaging with histogram-based phase correction |
Country Status (4)
Country | Link |
---|---|
US (1) | US7301340B2 (en) |
EP (1) | EP1623246A1 (en) |
JP (1) | JP2006522638A (en) |
WO (1) | WO2004090565A1 (en) |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN103814303A (en) * | 2011-07-08 | 2014-05-21 | 明尼苏达大学董事会 | Multistep correction for angle consistent artifacts in radial sampled image datasets |
Families Citing this family (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US7977943B2 (en) * | 2008-04-10 | 2011-07-12 | General Electric Company | Method and system for reconstructing images |
US9974608B2 (en) * | 2013-08-27 | 2018-05-22 | Biosense Webster (Israel) Ltd. | Determining absence of contact for a catheter |
EP3599586B1 (en) * | 2018-07-24 | 2020-10-14 | Siemens Healthcare GmbH | Method and device for analysis of magnetic resonance images |
Family Cites Families (9)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPS62148658A (en) | 1985-12-23 | 1987-07-02 | 株式会社日立製作所 | Examination method using nuclear magnetic resonance |
US6249595B1 (en) * | 1998-01-22 | 2001-06-19 | General Electric Company | Iterative reconstruction for EPI |
JP3353826B2 (en) * | 1999-06-24 | 2002-12-03 | ジーイー横河メディカルシステム株式会社 | Magnetic field inhomogeneity measurement device, phase correction device, and magnetic resonance imaging device |
JP3534669B2 (en) * | 2000-01-27 | 2004-06-07 | ジーイー・メディカル・システムズ・グローバル・テクノロジー・カンパニー・エルエルシー | Magnetic resonance imaging device |
US6486667B1 (en) * | 2000-03-31 | 2002-11-26 | Koninklijke Philips Electronics N.V. | Combination of fluid-attenuated inversion-recovery complex images acquired using magnetic resonance imaging |
US6307369B1 (en) * | 2000-07-12 | 2001-10-23 | Mayo Foundation For Medical Education And Research | Autocorrection of 3D MR images for motion artifacts |
US6411089B1 (en) * | 2000-11-22 | 2002-06-25 | Philips Medical Systems (Cleveland), Inc. | Two-dimensional phase-conjugate symmetry reconstruction for 3d spin-warp, echo-planar and echo-volume magnetic resonance imaging |
DE10122874B4 (en) * | 2001-05-11 | 2004-09-23 | Siemens Ag | Process for extracting spin collectives with different chemical shifts from phase-coded individual images, taking into account field inhomogeneities, and device therefor |
JP3968352B2 (en) * | 2004-02-03 | 2007-08-29 | ジーイー・メディカル・システムズ・グローバル・テクノロジー・カンパニー・エルエルシー | MRI equipment |
-
2004
- 2004-04-05 US US10/553,327 patent/US7301340B2/en not_active Expired - Fee Related
- 2004-04-05 WO PCT/IB2004/050394 patent/WO2004090565A1/en active Application Filing
- 2004-04-05 EP EP04725774A patent/EP1623246A1/en not_active Withdrawn
- 2004-04-05 JP JP2006506814A patent/JP2006522638A/en not_active Withdrawn
Non-Patent Citations (3)
Title |
---|
AHN C B ET AL: "NEW PHASE CORRECTION METHOD IN NMR IMAGING BASED ON AUTOCORRELATIONAND HISTOGRAM ANALYSIS", IEEE TRANSACTIONS ON MEDICAL IMAGING, IEEE INC. NEW YORK, US, vol. MI-6, no. 1, March 1987 (1987-03-01), pages 32 - 36, XP000611030, ISSN: 0278-0062 * |
FOXALL D L ET AL: "RAPID ITERACTIVE RECONSTRUCTION FOR ECHO PLANAR IMAGING", MAGNETIC RESONANCE IN MEDICINE, ACADEMIC PRESS, DULUTH, MN, US, vol. 42, no. 3, September 1999 (1999-09-01), pages 541 - 547, XP000859168, ISSN: 0740-3194 * |
JUWHAN LIU ET AL: "AN AUTOMATIC PHASE CORRECTION METHOD IN NUCLEAR MAGNETIC RESONANCE IMAGING", JOURNAL OF MAGNETIC RESONANCE, ACADEMIC PRESS, ORLANDO, FL, US, vol. 86, no. 3, 15 February 1990 (1990-02-15), pages 593 - 604, XP000132485, ISSN: 1090-7807 * |
Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN103814303A (en) * | 2011-07-08 | 2014-05-21 | 明尼苏达大学董事会 | Multistep correction for angle consistent artifacts in radial sampled image datasets |
CN103814303B (en) * | 2011-07-08 | 2016-08-17 | 明尼苏达大学董事会 | The more corrective of the angular consistent artifact that radial direction sampling image data is concentrated |
Also Published As
Publication number | Publication date |
---|---|
EP1623246A1 (en) | 2006-02-08 |
US20060197525A1 (en) | 2006-09-07 |
US7301340B2 (en) | 2007-11-27 |
JP2006522638A (en) | 2006-10-05 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
US10444315B2 (en) | MRI with motion correction using navigators acquired using a dixon technique | |
US9050018B2 (en) | Means and methods for providing high resolution MRI | |
JP5731373B2 (en) | Real-time local and global SAR estimation for improved patient safety and scanning performance | |
JP5809166B2 (en) | Method for calculating local energy specific absorption rate (SAR) in nuclear magnetic resonance | |
EP2648014A1 (en) | MR imaging using APT contrast enhancement and sampling at multiple echo times | |
EP2798364B1 (en) | Mr imaging with suppression of flow artefacts | |
US20130088230A1 (en) | Method of reconstructing a magnetic resonance image of an object considering higher-order dynamic fields | |
EP0271123A1 (en) | Method and arrangement for determining a corrected MRI surface coil image | |
US20170108571A1 (en) | Epi ghost correction involving sense | |
JP2016504144A (en) | Metal resistant MR imaging | |
WO2011055268A1 (en) | Mr imaging using navigators | |
CN111329479B (en) | Method for providing MR images, magnetic resonance imaging device and medium | |
JP6814325B2 (en) | Dixon type water / fat separation MR imaging | |
JP4679158B2 (en) | Magnetic resonance imaging system | |
US7301340B2 (en) | Magnetic resonance imaging with histogram-based phase correction | |
JP2007282860A (en) | Magnetic resonance imaging device and method | |
JP4481591B2 (en) | Method, system and computer product for gradient nonlinearity k-space correction | |
CN113466768B (en) | Magnetic resonance imaging method and magnetic resonance imaging system | |
EP3185029A1 (en) | Mr imaging using propeller acquisition with t2 decay correction | |
US11360172B2 (en) | Zero echo time MR imaging with water-fat separation | |
US20050007113A1 (en) | Magnetic resonance imaging method involving sub-sampling | |
EP3688479B1 (en) | Dixon-type water/fat separation mr imaging with improved fat shift correction | |
EP4012434A1 (en) | Dixon-type water/fat separation mr imaging | |
EP3995846A1 (en) | Spin echo mr imaging with spiral acquisition | |
US6268729B1 (en) | Correction of magnetic resonance signals in a magnetic resonance imaging method, and a magnetic resonance device |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
AK | Designated states |
Kind code of ref document: A1 Designated state(s): AE AG AL AM AT AU AZ BA BB BG BR BW BY BZ CA CH CN CO CR CU CZ DE DK DM DZ EC EE EG ES FI GB GD GE GH GM HR HU ID IL IN IS JP KE KG KP KR KZ LC LK LR LS LT LU LV MA MD MG MK MN MW MX MZ NA NI NO NZ OM PG PH PL PT RO RU SC SD SE SG SK SL SY TJ TM TN TR TT TZ UA UG US UZ VC VN YU ZA ZM ZW |
|
AL | Designated countries for regional patents |
Kind code of ref document: A1 Designated state(s): BW GH GM KE LS MW MZ SD SL SZ TZ UG ZM ZW AM AZ BY KG KZ MD RU TJ TM AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HU IE IT LU MC NL PL PT RO SE SI SK TR BF BJ CF CG CI CM GA GN GQ GW ML MR NE SN TD TG |
|
121 | Ep: the epo has been informed by wipo that ep was designated in this application | ||
WWE | Wipo information: entry into national phase |
Ref document number: 2004725774 Country of ref document: EP |
|
WWE | Wipo information: entry into national phase |
Ref document number: 2006506814 Country of ref document: JP |
|
WWE | Wipo information: entry into national phase |
Ref document number: 10553327 Country of ref document: US |
|
WWP | Wipo information: published in national office |
Ref document number: 2004725774 Country of ref document: EP |
|
WWP | Wipo information: published in national office |
Ref document number: 10553327 Country of ref document: US |