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Yoen H, Lee JM, Lee SM, Kang HJ, Bae JS, Kim E, Peeters JM, Yoon JH. Comparisons between image quality and diagnostic performance of 2D- and breath-hold 3D magnetic resonance cholangiopancreatography at 3T. Eur Radiol 2021; 31:8399-8407. [PMID: 33884471 DOI: 10.1007/s00330-021-07968-w] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2020] [Revised: 03/10/2021] [Accepted: 03/31/2021] [Indexed: 11/26/2022]
Abstract
OBJECTIVES To compare the image quality and diagnostic performance of 2D MRCP to those of breath-hold 3D MRCP using compressed sensing (CS-MRCP) and gradient and spin-echo (GRASE-MRCP) at 3T. METHODS From January to November 2018, patients who underwent pancreatobiliary MRI including 2D MRCP and two breath-hold 3D MRCP using CS and GRASE at 3T were included. Three radiologists independently evaluated image quality, motion artifact, and pancreatic cyst conspicuity. Diagnostic performance was assessed for bile duct anatomic variation, bile duct, and pancreatic diseases using a composite algorithm as reference standards. Pancreatic lesion detectability and conspicuity were evaluated using JAFROC and generalized estimating equation analysis. RESULTS One hundred patients (male = 50) were included. Bile duct anatomic variation, bile duct and pancreatic diseases were present in respectively 31, 15, and 79 patients. Breath-hold 3D MRCP provided better image quality than 2D MRCP (3.5 ± 0.6 in 2D MRCP; 4.0 ± 0.7 in GRASE-MRCP and 3.9 ± 0.8 in CS-MRCP, p < 0.001 for both). There was no difference in motion artifact between 2D and breath-hold 3D MRCP (p = 0.1). Breath-hold 3D CS-MRCP provided better pancreatic cyst conspicuity than 2D MRCP (2.7 [95% CI: 2.5-3.0] vs. 2.3 [95% CI: 2.1-2.5], p = 0.001). There were no significant differences between the diagnostic performance of the three sequences in the detection of bile duct anatomic variation or pancreatic lesions (p > 0.05). CONCLUSION Breath-hold 3D MRCP with GRASE or CS can provide better image quality than 2D MRCP in a comparable scan time. KEY POINTS • Breath-hold 3D MRCP using compressed sensing (CS) or gradient and spin-echo (GRASE) provided a better image quality with less image blurring than 2D MRCP. • There were no significant differences between 2D MRCP and breath-hold 3D MRCP in either motion artifact or the number of non-diagnostic exams. • There were no significant differences between 2D MRCP and either type of breath-hold 3D MRCP in the diagnosis of bile duct anatomic variation or detection of pancreatic lesions.
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Affiliation(s)
- Heera Yoen
- Department of Radiology, Seoul National University Hospital, 101 Daehak-ro, Jongno-gu, Seoul, 03080, Republic of Korea
| | - Jeong Min Lee
- Department of Radiology, Seoul National University Hospital, 101 Daehak-ro, Jongno-gu, Seoul, 03080, Republic of Korea
- Department of Radiology, Seoul National University College of Medicine, 103 Daehak-ro, Jongno-gu, Seoul, 03087, Republic of Korea
- Institute of Radiation Medicine, Seoul National University Medical Research Center, 103 Daehak-ro, Jongno-gu, Seoul, 03087, Republic of Korea
| | - Sang Min Lee
- Department of Radiology, Hallym University Sacred Heart Hospital, Anyang, Gyunggi-do, 14068, Republic of Korea
| | - Hyo-Jin Kang
- Department of Radiology, Seoul National University Hospital, 101 Daehak-ro, Jongno-gu, Seoul, 03080, Republic of Korea
- Department of Radiology, Seoul National University College of Medicine, 103 Daehak-ro, Jongno-gu, Seoul, 03087, Republic of Korea
| | - Jae Seok Bae
- Department of Radiology, Seoul National University Hospital, 101 Daehak-ro, Jongno-gu, Seoul, 03080, Republic of Korea
- Department of Radiology, Seoul National University College of Medicine, 103 Daehak-ro, Jongno-gu, Seoul, 03087, Republic of Korea
| | - Eunju Kim
- Philips Healthcare, Seoul, 04637, Republic of Korea
| | | | - Jeong Hee Yoon
- Department of Radiology, Seoul National University Hospital, 101 Daehak-ro, Jongno-gu, Seoul, 03080, Republic of Korea.
- Department of Radiology, Seoul National University College of Medicine, 103 Daehak-ro, Jongno-gu, Seoul, 03087, Republic of Korea.
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Jabarkheel R, Tong E, Lee EH, Cullen TM, Yousaf U, Loening AM, Taviani V, Iv M, Grant GA, Holdsworth SJ, Vasanawala SS, Yeom KW. Variable Refocusing Flip Angle Single-Shot Imaging for Sedation-Free Fast Brain MRI. AJNR Am J Neuroradiol 2020; 41:1256-1262. [PMID: 32586967 DOI: 10.3174/ajnr.a6616] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2019] [Accepted: 04/18/2020] [Indexed: 11/07/2022]
Abstract
BACKGROUND AND PURPOSE Conventional single-shot FSE commonly used for fast MRI may be suboptimal for brain evaluation due to poor image contrast, SNR, or image blurring. We investigated the clinical performance of variable refocusing flip angle single-shot FSE, a variation of single-shot FSE with lower radiofrequency energy deposition and potentially faster acquisition time, as an alternative approach to fast brain MR imaging. MATERIALS AND METHODS We retrospectively compared half-Fourier single-shot FSE with half- and full-Fourier variable refocusing flip angle single-shot FSE in 30 children. Three readers reviewed images for motion artifacts, image sharpness at the brain-fluid interface, and image sharpness/tissue contrast at gray-white differentiation on a modified 5-point Likert scale. Two readers also evaluated full-Fourier variable refocusing flip angle single-shot FSE against T2-FSE for brain lesion detectability in 38 children. RESULTS Variable refocusing flip angle single-shot FSE sequences showed more motion artifacts (P < .001). Variable refocusing flip angle single-shot FSE sequences scored higher regarding image sharpness at brain-fluid interfaces (P < .001) and gray-white differentiation (P < .001). Acquisition times for half- and full-Fourier variable refocusing flip angle single-shot FSE were faster than for single-shot FSE (P < .001) with a 53% and 47% reduction, respectively. Intermodality agreement between full-Fourier variable refocusing flip angle single-shot FSE and T2-FSE findings was near-perfect (κ = 0.90, κ = 0.95), with an 8% discordance rate for ground truth lesion detection. CONCLUSIONS Variable refocusing flip angle single-shot FSE achieved 2× faster scan times than single-shot FSE with improved image sharpness at brain-fluid interfaces and gray-white differentiation. Such improvements are likely attributed to a combination of improved contrast, spatial resolution, SNR, and reduced T2-decay associated with blurring. While variable refocusing flip angle single-shot FSE may be a useful alternative to single-shot FSE and, potentially, T2-FSE when faster scan times are desired, motion artifacts were more common in variable refocusing flip angle single-shot FSE, and, thus, they remain an important consideration before clinical implementation.
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Affiliation(s)
- R Jabarkheel
- From the Stanford University School of Medicine (R.J.)
| | - E Tong
- Departments of Radiology (E.T., A.M.L., V.T., M.I.)
| | - E H Lee
- Electrical Engineering (E.H.L.)
| | - T M Cullen
- Department of Radiology (T.M.C., U.Y., S.S.V., K.W.Y.), Lucile Packard Children's Hospital, Stanford University, Palo Alto, California
| | - U Yousaf
- Department of Radiology (T.M.C., U.Y., S.S.V., K.W.Y.), Lucile Packard Children's Hospital, Stanford University, Palo Alto, California
| | - A M Loening
- Departments of Radiology (E.T., A.M.L., V.T., M.I.)
| | - V Taviani
- Departments of Radiology (E.T., A.M.L., V.T., M.I.)
| | - M Iv
- Departments of Radiology (E.T., A.M.L., V.T., M.I.)
| | - G A Grant
- Neurosurgery (G.A.G.), Stanford University, Stanford, California
| | - S J Holdsworth
- Department of Anatomy and Medical Imaging and Centre for Brain Research (S.J.H.), Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand
| | - S S Vasanawala
- Department of Radiology (T.M.C., U.Y., S.S.V., K.W.Y.), Lucile Packard Children's Hospital, Stanford University, Palo Alto, California
| | - K W Yeom
- Department of Radiology (T.M.C., U.Y., S.S.V., K.W.Y.), Lucile Packard Children's Hospital, Stanford University, Palo Alto, California
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Chu ML, Chien CP, Wu WC, Chung HW. Gradient- and spin-echo (GRASE) MR imaging: a long-existing technology that may find wide applications in modern era. Quant Imaging Med Surg 2019; 9:1477-1484. [PMID: 31667134 DOI: 10.21037/qims.2019.09.13] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Affiliation(s)
- Mei-Lan Chu
- Graduate Institute of Biomedical Electronics and Bioinformatics, National Taiwan University, Taipei, Taiwan.,Department of Biomedical Sciences and Engineering, National Central University, Taoyuan, Taiwan
| | - Cheng-Ping Chien
- Graduate Institute of Biomedical Electronics and Bioinformatics, National Taiwan University, Taipei, Taiwan.,Department of Radiology, Taipei Beitou Health Management Hospital, Taipei, Taiwan
| | - Wen-Chau Wu
- Institute of Medical Device and Imaging, National Taiwan University, Taipei, Taiwan
| | - Hsiao-Wen Chung
- Graduate Institute of Biomedical Electronics and Bioinformatics, National Taiwan University, Taipei, Taiwan
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Bagnato F, Hametner S, Pennell D, Dortch R, Dula AN, Pawate S, Smith SA, Lassmann H, Gore JC, Welch EB. 7T MRI-Histologic Correlation Study of Low Specific Absorption Rate T2-Weighted GRASE Sequences in the Detection of White Matter Involvement in Multiple Sclerosis. J Neuroimaging 2015; 25:370-8. [PMID: 25898858 DOI: 10.1111/jon.12238] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2014] [Accepted: 02/12/2015] [Indexed: 12/27/2022] Open
Abstract
BACKGROUND The high value of the specific absorption rate (SAR) of radio-frequency (RF) energy arising from the series of RF refocusing pulses in T2-weighted (T2-w) turbo spin echo (TSE) MRI hampers its clinical application at 7.0 Tesla (7T). T2-w gradient and spin echo (GRASE) uses the speed from gradient refocusing in combination with the chemical-shift/static magnetic field (B0) inhomogeneity insensitivity from spin-echo refocusing to acquire T2-w images with a limited number of refocusing RF pulses, thus reducing SAR. OBJECTIVES To investigate whether low SAR T2-w GRASE could replace T2-w TSE in detecting white matter (WM) disease in MS patients imaged at 7T. METHODS The .7 mm3 isotropic T2-w TSE and T2-w GRASE images with variable echo times (TEs) and echo planar imaging (EPI) factors were obtained on a 7T scanner from postmortem samples of MS brains. These samples were derived from brains of 3 female MS patients. WM lesions (WM-Ls) and normal-appearing WM (NAWM) signal intensity, WM-Ls/NAWM contrast-to-noise ratio (CNR) and MRI/myelin staining sections comparisons were obtained. RESULTS GRASE sequences with EPI factor/TE = 3/50 and 3/75 ms were comparable to the SE technique for measures of CNR in WM-Ls and NAWM and for detection of WM-Ls. In all sequences, however, identification of areas with remyelination, Wallerian degeneration, and gray matter demyelination, as depicted by myelin staining, was not possible. CONCLUSIONS T2-w GRASE images may replace T2-w TSE for clinical use. However, even at 7T, both sequences fail in detecting and characterizing MS disease beyond visible WM-Ls.
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Affiliation(s)
- Francesca Bagnato
- Vanderbilt University Institute of Imaging Science, Department of Radiology and Radiological Sciences, Vanderbilt University Medical Center, Nashville, TN
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Trampel R, Reimer E, Huber L, Ivanov D, Heidemann RM, Schäfer A, Turner R. Anatomical brain imaging at 7T using two-dimensional GRASE. Magn Reson Med 2013; 72:1291-301. [DOI: 10.1002/mrm.25047] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2013] [Revised: 10/25/2013] [Accepted: 10/27/2013] [Indexed: 11/09/2022]
Affiliation(s)
- Robert Trampel
- Max Planck Institute for Human Cognitive and Brain Sciences; Leipzig Germany
| | - Enrico Reimer
- Max Planck Institute for Human Cognitive and Brain Sciences; Leipzig Germany
| | - Laurentius Huber
- Max Planck Institute for Human Cognitive and Brain Sciences; Leipzig Germany
| | - Dimo Ivanov
- Maastricht Brain Imaging Centre; Maastricht University; Maastricht The Netherlands
| | | | - Andreas Schäfer
- Max Planck Institute for Human Cognitive and Brain Sciences; Leipzig Germany
| | - Robert Turner
- Max Planck Institute for Human Cognitive and Brain Sciences; Leipzig Germany
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Prasloski T, Rauscher A, MacKay AL, Hodgson M, Vavasour IM, Laule C, Mädler B. Rapid whole cerebrum myelin water imaging using a 3D GRASE sequence. Neuroimage 2012; 63:533-9. [PMID: 22776448 DOI: 10.1016/j.neuroimage.2012.06.064] [Citation(s) in RCA: 193] [Impact Index Per Article: 16.1] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2012] [Revised: 06/25/2012] [Accepted: 06/28/2012] [Indexed: 11/30/2022] Open
Affiliation(s)
- Thomas Prasloski
- Department of Physics and Astronomy, University of British Columbia, 6224 Agricultural Road, Vancouver, BC, Canada V6T 1Z1.
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Held P, Seitz J, Fründ R, Nitz W, Lenhart M, Geissler A. Comparison of two-dimensional gradient echo, turbo spin echo and two-dimensional turbo gradient spin echo sequences in MRI of the cervical spinal cord anatomy. Eur J Radiol 2001; 38:64-71. [PMID: 11287168 DOI: 10.1016/s0720-048x(00)00253-9] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
The aim of this study was to assess the detectability and distinguishability of the cervical spinal cord, the anterior and posterior spinal roots and of the internal anatomy of the cord (distinction of grey and white matter). For this purpose 20 healthy volunteers were examined using a 1.5 T MR unit with 20 mT/m gradient strength and a dedicated circular polarized neck array coil. Three T2* weighted (w). 2D gradient echo sequences, two T2 w. 2D turbo spin echo (TSE) sequences and one T2 w. 2D turbo gradient spin echo (TGSE) sequence were compared. The multiecho 2D fast low angle shot (FLASH) sequence with magnetization transfer saturation pulse (me FLASH+MTS) yielded the best results for liquor/compact bone, liquor/spinal cord and grey/white matter contrast, as found with regions of interest (ROI) analysis. The single echo 2D FLASH sequence was significantly poorer than the two me FLASH+/-MTS sequences. Two-dimensional TGSE as well as 2D TSE with a 256 matrix and with a 512 matrix yielded the poorest results. In the visual analysis the contrast between liquor and compact bone, liquor and cord as well as liquor and roots was best with me FLASH+MTS, whereas grey/white matter distinction was best using me FLASH-MTS. In conclusion, we would therefore recommend the inclusion of an axial T2* w. multiecho 2D spoiled gradient echo sequence with magnetization transfer saturation pulse and gradient motion rephasing in a MR imaging protocol of the cervical spine.
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Affiliation(s)
- P Held
- Department of Diagnostic Radiology, University of Regensburg, University Hospital, 93042, Regensburg, Germany
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8
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Yanagawa Y, Tsushima Y, Tokumaru A, Un-no Y, Sakamoto T, Okada Y, Nawashiro H, Shima K. A quantitative analysis of head injury using T2*-weighted gradient-echo imaging. THE JOURNAL OF TRAUMA 2000; 49:272-7. [PMID: 10963538 DOI: 10.1097/00005373-200008000-00013] [Citation(s) in RCA: 88] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
BACKGROUND T2*-weighted gradient-echo imaging (T2*-GE) is useful for detecting small hemorrhages. METHODS Thirty-four patients were prospectively examined, first by magnetic resonance imaging (1.5 T) and then by T2-weighted fast spin echo (T2-FSE) and T2*-GE. Thereafter, the correlations between the T2-FSE or T2*-GE findings and the clinical or computed tomography findings were analyzed. RESULTS The number of lesions detected by T2*-GE was 14.5 +/- 16.3 (mean +/- SD, n = 34), which was significantly (p < 0.001) greater than that detected by T2-FSE (5.6 +/- 5.6, n = 34). The findings of T2*-GE correlated positively with both the duration of unconsciousness (R2 = 0.74,p < 0.0001) and with Glasgow Outcome Scale (R2 = 0.81, p < 0.0001), whereas those of T2-FSE did not show any significant correlation. T2*-GE imaging could also detect all areas responsible for focal neurologic signs 1 month after in. jury, whereas T2-FSE imaging detected only 22 of 33 such signs. CONCLUSION T2*-GE was found to be useful for evaluating the clinical symptoms of head injury.
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Affiliation(s)
- Y Yanagawa
- Department of Traumatology and Critical Care Medicine, National Defense Medical College, Saitama, Japan
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Rovaris M, Rocca MA, Yousry I, Yousry TA, Colombo B, Comi G, Filippi M. Lesion load quantification on fast-FLAIR, rapid acquisition relaxation-enhanced, and gradient spin echo brain MRI scans from multiple sclerosis patients. Magn Reson Imaging 1999; 17:1105-10. [PMID: 10499672 DOI: 10.1016/s0730-725x(99)00068-5] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Previous studies have addressed the issue of the usefullness of fast fluid-attenuated (fast-FLAIR), rapid acquisition relaxation-enhanced (RARE), and gradient spin echo (GRASE) sequences in small groups of patients with multiple sclerosis (MS). The aim of this study was to assess and compare the lesion volumes and the intra-rater reproducibility of such measurements using fast-FLAIR, dual echo RARE, and dual echo GRASE brain scans from a large sample of MS patients. Using a 1.5 Tesla scanner, fast-FLAIR, dual echo RARE, and dual echo GRASE scans (24 axial, 5-mm thick contiguous interleaved slices) of the brain were obtained from 50 MS patients. Total lesion loads (TLL) were assessed twice using a semi-automated local thresholding segmentation technique by the same rater from the scans obtained with the three techniques. Mean TLL were 20.3 mL for fast-FLAIR, 16.6 mL for RARE, and 17.6 mL for GRASE sequences. Mean TLL detected by the three techniques were significantly heterogeneous (p < 0.001); at post-hoc analysis, the mean lesion volume detected on fast-FLAIR images was significantly higher than that on both RARE and GRASE images (p < 0.001) and the mean TLL on GRASE scans was significantly higher than that on RARE scans (p = 0.001). The mean values of intra-observer coefficient of variation for TLL measurements were similar for the three techniques (2.69% for fast-FLAIR, 2.33% for RARE, and 2.65% for GRASE). Our results confirm that fast-FLAIR sequences detect higher lesion volumes than those detected by other magnetic resonance imaging (MRI) sequences with shorter acquisition times. However, the reproducibility of TLL measurements is comparable among fast-FLAIR, RARE, and GRASE. This suggests that when assessing MS disease burden with MRI, the choice of the pulse sequence to be used should be dictated by the clinical setting.
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Affiliation(s)
- M Rovaris
- Department of Neuroscience, Scientific Institute Ospedale San Raffaele, Milan, Italy
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Abstract
This article reviews fast magnetic resonance (MR) techniques currently used for body imaging. Improvements in gradient performance have made very short repetition and echo times on clinical scanners feasible, thus enabling subsecond image acquisition. The article provides a fundamental overview of the technical aspects from the concept of k-space and k-space segmentation technique, fast MR imaging techniques including fast spin echo, fast gradient echo with or without magnetization preparation to echo planar and hybrid techniques. The article also addresses the use of different fat suppression techniques in MR imaging of the body and improvements in coil technology to obtain faster images and higher signal-to-noise.
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Affiliation(s)
- Q Chen
- Department of Radiology, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, MA 02215, USA
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Mathews VP, Greenspan SL, Caldemeyer KS, Patel MR. FLAIR AND HASTE IMAGING IN NEUROLOGIC DISEASES. Magn Reson Imaging Clin N Am 1998. [DOI: 10.1016/s1064-9689(21)00444-x] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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Fellner F, Held P, Fellner C, Schmitt R, Obletter N. Fast spin-echo (FSE) and gradient- and spin-echo (GRASE) in fast MRI of the pelvis. Magn Reson Imaging 1997; 15:517-24. [PMID: 9253995 DOI: 10.1016/s0730-725x(97)00003-9] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
In this prospective study two different T2-weighted fast spin-echo (FSE) sequences and a gradient- and spin-echo (GRASE) sequence were compared in 20 consecutive patients undergoing clinical pelvic MR examinations. A GRASE and two FSE sequences were applied, whereby the FSE sequences differed from each other by altered echo spacings (15.0 and 22.5 ms) and T2 contrast. Quantitative image analysis included ROI evaluation of different S/N and C/N values. Visual image analysis was performed by two independent readers using a standardized score sheet for anatomic and pathologic findings. Overall image quality was significantly better in both FSE sequences. GRASE and FSE22.5 were superior in delineation of most of anatomic and pathologic structures due to intermediate to hypointense contrast behavior of pelvic fat compared to FSE15.0 in which fat was bright. Therefore, FSE15.0 was optimal for low intensity lesions. Short acquisition times of FSE and GRASE sequences allow application of two different techniques-fat hypointense respectively bright-for excellent lesion visualisation. This study demonstrates the usefulness of contrast manipulation in fast T2-weighted MRI techniques without special techniques, such as fat saturation.
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Affiliation(s)
- F Fellner
- Department of Diagnostic Radiology, Friedrich-Alexander-University of Erlangen-Nurnberg, Erlangen, Germany.
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Hittmair K, Umek W, Schindler EG, Ba-Ssalamah A, Pretterklieber ML, Herold CJ. Fast flair imaging of the brain using the fast spin-echo and gradient spin-echo technique. Magn Reson Imaging 1997; 15:405-14. [PMID: 9223041 DOI: 10.1016/s0730-725x(96)00381-5] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
The purpose of this study was to compare the gradient spin-echo (GRASE) to the fast spin-echo (FSE) implementation of fast fluid-attenuated inversion recovery (FLAIR) sequences for brain imaging. Thirty patients with high signal intensity lesions on T2-weighted images were examined on a 1.5 T MR system. Scan time-minimized thin-section FLAIR-FSE and FLAIR-GRASE sequences were obtained and compared side by side. Image assessment criteria were lesion conspicuity, contrast between different types of normal tissue, image quality, and artifacts. In addition, contrast ratios and contrast-to-noise ratios were determined. Compared to FSF, the GRASE technique allowed a 17% reduction in scan time but conspicuity of small lesions in particular was significantly lower on FLAIR-GRASE images because of higher image noise and increased artifacts. Gray-white differentiation was slightly worse on FLAIR-GRASE. Physiological ferritin deposition appeared slightly darker on FLAIR-GRASE images and susceptibility artifacts were stronger. Fatty tissue was less bright with FLAIR-GRASE. With current standard hardware equipment, the GRASE technique is not an adequate alternative to FSE for the implementation of fast FLAIR sequences in routine clinical MR brain imaging.
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Affiliation(s)
- K Hittmair
- Department of Neuroradiology, University of Vienna, Austria
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