共查询到20条相似文献,搜索用时 0 毫秒
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OBJECTIVE: To compare fast T1-weighted fluid-attenuated inversion recovery (FLAIR) and T1-weighted turbo spin-echo (TSE) imaging of the degenerative disc disease of the lumbar spine. MATERIALS AND METHODS: Thirty-five consecutive patients (19 females, 16 males; mean age 41 years, range 31-67 years) with suspected degenerative disc disease of the lumbar spine were prospectively evaluated. Sagittal images of the lumbar spine were obtained using T1-weighted TSE and fast T1-weighted FLAIR sequences. Two radiologists compared these sequences both qualitatively and quantitatively. RESULTS: On qualitative evaluation, CSF nulling, contrast at the disc-CSF interface, the disc-spinal cord (cauda equina) interface, and the spinal cord (cauda equina)-CSF interface of fast T1-weighted FLAIR images were significantly higher than those for T1-weighted TSE images (P<0.001). On quantitative evaluation of the first 15 patients, signal-to-noise ratios of cerebrospinal fluid of fast T1-weighted FLAIR imaging were significantly lower than those for T1-weighted TSE images (P<0.05). Contrast-to-noise ratios of spinal cord/CSF and normal bone marrow/disc for fast T1-weighted FLAIR images were significantly higher than those for T1-weighted TSE images (P<0.05). CONCLUSION: Results in our study have shown that fast T1-weighted FLAIR imaging may be a valuable imaging modality in the armamentarium of lumbar spinal T1-weighted MR imaging, because the former technique has definite superior advantages such as CSF nulling, conspicuousness of the normal anatomic structures and changes in the lumbar spinal discogenic disease and image contrast and also almost equally acquisition times. 相似文献
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Ascher SM O'Malley J Semelka RC Patt RH Rajan S Thomasson D 《Journal of magnetic resonance imaging : JMRI》1999,9(3):384-390
This study compared one routine T2-weighted fast spin echo (T2FSE) sequence with a breath-hold T2FSE (BH T2FSE) sequence of the female pelvis for image quality, uterine anatomy, lesion detection, and signal intensity measurements. Thirty-two consecutive women (mean age 41.7 years) were imaged at 1.5 T with one high-resolution routine T2FSE sequence and one BH T2FSE sequence in the sagittal plane as part of comprehensive pelvic magnetic resonance imaging. The different image sets were rated separately for imaging characteristics (overall image quality, uterine anatomy definition, lesion detection, and free fluid conspicuity) and then compared side by side. The image sets were also compared for artifacts (ghosting, blurring, pulsatility, and chemical shift misregistration). Signal-to-noise (S/N) and signal difference-to-noise (SD/N) ratios were calculated for the different uterine zones, uterine abnormalities, free fluid, rectus abdominis muscle, and bladder. Contrast-to-noise ratios (CNRs) were calculated for uterine abnormalities. Twenty-eight uterine abnormalities were detected in 20 patients and included leiomyomata (13 patients), adenomyosis (7 patients), benign endometrial polyps (6 patients), endometrial carcinoma (1 patient), and pregnancy (1 patient). BH T2FSE was superior or equivalent to T2FSE for overall image quality in 23/32 patients (71.8%), uterine anatomy definition in 19/32 patients (59.3%), and lesion detection in 13/20 patients (65%). BH T2FSE performed less well than T2FSE for free fluid conspicuity in 5/5 (100%) patients. BH T2FSE was equivalent to or less affected than T2FSE for ghosting artifact in 24/32 patients (75%) and blurring artifact in 29/32 patients (90.6%). Pulsatility and chemical shift artifacts were not problematic for either image set. S/N and SD/N were higher for all BH T2FSE determinations compared with T2FSE. For the endometrium, junctional zone, myometrium, and bladder, these differences were statistically significant. There were no statistically significant differences for CNR between the two image sets, although BH T2FSE values for leiomyomata, adenomyosis, and abnormal endometria were higher than those calculated for T2FSE. All pathology detected with T2FSE was detected on BH T2FSE despite the breath-hold sequence's inherently poorer spatial resolution compared with the non-breath-hold sequence. BH T2FSE may be able to replace T2FSE for some uterine applications with a substantial time savings. 相似文献
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PURPOSE: To compare breath-hold fast-recovery fast spin echo (FR-FSE) and non-breath-hold fast spin echo (FSE) T2-weighted sequences for hepatic lesion conspicuity and image quality at MR imaging. MATERIALS AND METHODS: Fifty-nine patients with known or suspected liver lesions underwent hepatic MR imaging by using a breath-hold FR-FSE T2-weighted sequence with and without fat suppression and a non-breath-hold FSE T2-weighted sequence with and without fat suppression. Quantitative analysis was made with measurements of the signal intensity of the liver, spleen, background noise, and up to three liver lesions, as well as calculations of the liver signal-to-noise ratio (SNR) and the liver-to-lesion contrast-to-noise ratio (CNR) for each sequence. Qualitative analysis was made for image quality and the number of lesions identified. Statistical analysis was performed by using a single-tailed paired Student's t test with a 95% confidence interval. RESULTS: SNR and CNR were significantly higher (P<.05) for FSE with fat suppression than for FR-FSE with fat suppression. No statistically significant difference was seen in terms of SNR and CNR between non-fat-suppressed FSE and FR-FSE sequences. Lesion conspicuity, liver edge sharpness, and clarity of vessels were superior and ghosting was less with the FR-FSE sequences compared with the FSE sequences. CONCLUSION: Breath-hold FR-FSE technique is a reasonable alternative in T2-weighted imaging of the liver. 相似文献
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Brain T1 mapping has important clinical applications in detecting brain disorders. Conventional T1 mapping techniques are usually based on inversion recovery spin echo (IRSE) imaging or its more time-efficient counterpart inversion recovery fast spin echo (IRFSE) imaging because they can deliver good image quality. Multiple inversion times are required to accurately estimate T1 over a wide range of values. Without acquisition optimization, both the IRSE and the IRFSE T1 mapping techniques require long scan times to image the whole brain. To reduce the scan time and maintain the quality of the T1 maps, we propose a new full-brain T1 mapping pulse sequence based on a multislice inversion recovery fast spin echo imaging using a time-efficient slice ordering technique. 相似文献
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T1-weighted fluid-attenuated inversion recovery at low field strength: a viable alternative for T1-weighted intracranial imaging 总被引:5,自引:0,他引:5
Hori M Okubo T Uozumi K Ishigame K Kumagai H Araki T 《AJNR. American journal of neuroradiology》2003,24(4):648-651
BACKGROUND AND PURPOSE: T1-weighted spin-echo imaging has been widely used to study anatomic detail and abnormalities of the brain; however, the image contrast of this technique is often poor, especially at low field strengths. We tested a new pulse sequence, T1-weighted fluid-attenuated inversion recovery (FLAIR), which provides good contrast between lesions, surrounding edematous tissue, and normal parenchyma at low field strengths and at acquisition times comparable to those of T1-weighted spin-echo imaging. METHODS: Thirteen patients with brain lesions underwent T1-weighted spin-echo and T1-weighted FLAIR imaging during the same imaging session. T1-weighted spin-echo and T1-weighted FLAIR images were compared on the basis of four quantitative (lesion-white matter [WM] contrast-to-noise ratio [CNR], lesion-CSF CNR, gray matter-WM CNR, and WM-CSF CNR) and three qualitative criteria (conspicuousness of lesions, image artifacts, and overall image contrast). RESULTS: CNRs obtained with T1-weighted FLAIR were comparable but statistically superior to those obtained with T1-weighted spin-echo imaging. In general, T1-weighted FLAIR and T1-weighted spin-echo imaging produced comparable image artifacts. Conspicuousness of lesions and the overall image contrast were judged to be superior on T1-weighted FLAIR images. CONCLUSION: T1-weighted FLAIR imaging may be a valuable alternative to conventional T1-weighted imaging, because the former technique offers superior image contrast at low field strengths and comparable acquisition times. 相似文献
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Fischbach F Bruhn H Unterhauser F Ricke J Wieners G Felix R Weiler A Schröder RJ 《Acta radiologica (Stockholm, Sweden : 1987)》2005,46(1):67-73
PURPOSE: To evaluate and compare the diagnostic accuracy of appropriate magnetic resonance (MR) sequences in the detection of cartilage lesions at 1.5T and 3.0T. MATERIAL AND METHODS: Twelve chondral defects of varying depths, widths, and locations were created in the retropatellar hyaline cartilage in six sheep cadaver limbs. Axial images employing three fat-suppressed imaging sequences--(1) a T2-weighted fast spin-echo (FSE) sequence, (2) a two-dimensional (2D) and (3) three-dimensional (3D) gradient-echo (GE) sequence at 1.5T and 3.0T using an extremity quadrature coil--were evaluated by three experienced radiologists. Statistical analysis of the results consisted of receiver operating characteristics (ROC) and significant testing using the bivariate chi-square test. In addition, signal-to-noise ratios (SNR) and contrast-to-noise ratios (CNR) were evaluated with significance testing using the Wilcoxon test. RESULTS: The 3D GE sequence compared favorably with other sequences at 3.0T and 1.5T (Az=0.88 at 3.0T and Az=0.85 at 1.5T) missing only one small grade 2 lesion. 2D GE imaging was inferior to 3D imaging at both field strengths (P<0.05) in general. However, compared to 1.5T, lesion detectability was improved at the higher magnetic field of 3.0T (Az=0.81 and 0.73 at 3.0T and 1.5T, respectively). FSE images showed significantly inferior sensitivity and less anatomical detail compared to the GE sequences at both field strengths (Az=0.64 and 0.72 at 3.0T and 1.5T, respectively; P<0.05). However, compared to 1.5T, lesion detectability SNR and CNR values were superior in all sequences tested at 3.0T. CONCLUSION: MRI at 3.0T improves SNR and CNR significantly in the most common sequences for cartilage MRI, resulting in an improvement in chondral lesion detection. GE imaging therefore allows resolution to be increased in an acceptable time manner for patient comfort, and the 3D GE fat-suppressed sequence at 3.0T appears to be best suited for cartilage imaging in a clinical setting. 相似文献
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PURPOSETo optimize a T1-weighted fast fluid-attenuated inversion recovery (FLAIR) sequence using computer-simulated data and to study its clinical utility for imaging the spine.METHODSRelative signal intensities and contrast of relevant normal and pathologic tissues in the spine were computed using an inversion recovery equation modified to account for a hybrid RARE (rapid acquisition with relaxation enhancement) readout. A range of inversion time (TI) and repetition time (TR) pairs that null the signal from CSF was generated. A contrast-optimized heavily T1-weighted fast FLAIR sequence, based on the generated data, was qualitatively compared with conventional T1-weighted spin-echo sequences for imaging various spinal abnormalities.RESULTSA T1/TR pair of approximately 862/2000 was extracted from the computer-generated data to produce effective nulling of CSF signal, to achieve heavy T1 weighting, and to optimize contrast between abnormal tissues and cord/bone marrow. Clinical implementation of the optimized T1-weighted fast FLAIR sequence revealed superior contrast at the CSF-cord interface, better conspicuity of lesions of the spinal cord and bone marrow, and reduced hardware-related artifacts as compared with conventional T1-weighted spin-echo sequences.CONCLUSIONThe optimized T1-weighted fast FLAIR technique has definite advantages over spin-echo sequences for imaging the spine. Comparable acquisition times render the FLAIR sequence the method of choice for T1-weighted imaging of the spine. 相似文献
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Simon EM McCaffery S Rowley HA Fischbein NJ Shimikawa A O'Brien JM 《Neuroradiology》2003,45(7):489-492
Recent developments have made available for ophthalmologic MR imaging a very high-resolution 3D fast spin echo T2 (3D FSE T2) sequence, which runs in a standard head coil. A modification of this technique, 3D FSEz T2, uses a zero-filled slice interpolation method during post-processing to further improve spatial resolution. We describe the technique and share our early clinical observations in patients with ocular masses. Briefly, the additional information from the 3D FSEz T2 resulted in a change in diagnosis from the conventional imaging series in 11 of (41%) 27 studies, usually through the identification of previously treated retinoblastoma lesions. The new sequence significantly increased diagnostic confidence in six (38%) of the remaining 16 cases, usually through better anatomical detail and lesion conspicuity, and did not change interpretation in 10 cases. Such an approach improves diagnostic confidence and may eliminate the need for a dedicated surface coil examination. 相似文献
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John Listerud Jim Mitchell Linda Bagley Robert Grossman 《Magnetic resonance in medicine》1996,36(2):320-325
Inversion recovery may be used to suppress signal from cerebrospinal fluid, a technique which has been named “fluid attenuated with inversion recovery” (FLAIR). This report describes interleaving a slice selective inversion pulse within a rapid spin-echo sequence to obtain the desirable contrast characteristics of FLAIR in imaging times comparable to standard rapid spin echo. Additionally, the pulse repetition time is allowed to float above a defined minimum, which can further shorten scan times and dramatically ease the optimization process. The optimized interleaved sequence is referred to as OIL FLAIR. 相似文献
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On abdominal MRI, since priority is given to time shortening during scanning breath-hold imaging, the signal-to-noise ratio (SNR) and resolution fall victim. We examined the RF power of the 90-degree pulse becomes the maximum signal of fat in T(1)-weighted imaging, and liver with a long T(1) value was noted not to have reached the maximum signal compared with fat. That is, without sacrificing scanning time and resolution by adjusting RF output so that liver would become the maximum signal, it was considered that the SNR of liver substance could be improved. In the phantom experiment, the difference in RF power from which fat and liver became the maximum signal was 1 dB at TR 400 msec. Although a decrease of 10% or less in the fat signal was produced by adding this difference to the RF power obtained by automatic pre-scan, the SNR of liver substance was improved. 相似文献
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Xiaohong Zhou Zhi-Pei Liang Sally L. Gewalt Gary P. Gofer Paul C. Lauterbur G. Allan Johnson 《Magnetic resonance in medicine》1998,39(1):23-27
This paper presents a fast spin echo (FSE) imaging method that employs circular sampling of Jr-space. The technique has been implemented on a 2 Tesla imaging system and validated on both phantoms and living animals. Experimental studies have shown that circular sampling can produce artifact-free FSE images without the need of phase correction. Although not fully explored, preliminary results also show that circular sampling may have advantages over the conventional rectilinear FSE in signal-to-noise ratio and imaging efficiency. A major disadvantage is the increased sensitivity to off-resonance effects. The authors expect that the FSE technique with circular sampling will find its applications in magnetic resonance microscopy, neuro-functional imaging, and real-time dynamic studies. 相似文献
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MRI of the pulmonary veins: comparison between 3D MR angiography and T1-weighted spin echo 总被引:3,自引:0,他引:3
OBJECTIVE: The purpose was to determine the ability of three-dimensional (3D) magnetic resonance (MR) angiography to depict normal pulmonary veins in comparison with spin-echo MR imaging. MATERIALS AND METHODS: MR imaging of 40 patients with cardiovascular disease were reviewed. Patients with known pulmonary venous abnormalities were excluded. Using a standard GE 1.5-T magnet, axial T1-weighted spin-echo 5-mm-thick contiguous slices and 3D MR angiography (contiguous slice thickness of 2.5-3.5 mm, 20-30 c.c. of gadolinium bolus at 1-1.5 c.c./sec, 32-43-second breath-hold, coronal and sagittal plane acquisition) were evaluated retrospectively on separate occasions by two experienced radiologists. Multiplanar imaging projection was used for the identification of pulmonary veins. Each lung was considered to have two drainage veins: a superior vein and an inferior vein. Identification of a pulmonary vein was made by visualizing a connection with the left atrium. RESULTS: 143 pulmonary veins (87.5% +/-5.2) were identified at the level of the left atrium on T1-weighted spin-echo images, and 157 (98.1% +/-1.9) were identified on 3D MR angiography (p<0.01). Overall we identified by T -weighted spin-echo imaging 36 right upper, 38 right lower, 27 left upper, and 38 left lower pulmonary veins. By 3D MR angiography, we identified 38 right upper, 40 right lower, 39 left upper, and 40 left lower pulmonary veins. All four pulmonary veins were detected in 22 patients on spin-echo imaging (55%) and in 37 patients (92.5%) on 3D MR angiography (chi = 3.81, p<0.05). CONCLUSION: A significant difference is demonstrated between 3D MR angiography and spin-echo MR imaging in identifying normal pulmonary veins. MR angiography provides a complete view of normal pulmonary venous anatomy and could be a valuable tool for the assessment of abnormal pulmonary venous drainage. 相似文献
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Objective To prospectively compare inversion recovery (IR) fast spin-echo (FSE) with T1-weighted spin-echo (SE) and T2-weighted chemical-shift
fat-saturated (FS) FSE magnetic resonance sequences in the detection of bone marrow abnormality. Design. Twenty-nine sets of T1-weighted SE [400–640/10–20 (TR/TE)], T2-weighted FS-FSE [2400–3800/91–112/8 (TR/TE/ETL)], and IR-FSE
[3700–6000/12–14/170/8 (TR/TE/T1/ETL)] images were acquired with a 1.5-T magnet in 27 patients with bone marrow lesions. The
visibility, margination, and extent of 41 lesions, image quality, contrast, and artifacts were qualitatively and quantitatively
compared. Results. The lesions were more conspicuous on the IR-FSE than on the T1-weighted SE and T2-weighed FS-FSE images. The extent of lesions
was similar for all three sequences. Image quality was better and there were fewer motion artifacts on the T1-weighted images.
The mean lesion contrast-to-noise ratio was significantly higher on the T1-weighted images (p<0.05). Conclusion. The IR-FSE sequence is highly sensitive for detecting bone marrow pathology, with scan time comparable to the T1-weighted
SE and T2-weighted FS-FSE sequences. 相似文献
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K Yamamoto T Shimizu Y Tanaka I Narabayashi 《Nihon Igaku Hōshasen Gakkai zasshi. Nippon acta radiologica》1999,59(7):313-317
The purpose of this study was to apply multishot echoplanar imaging (EPI) to the female pelvis and to compare the results with respiratory triggered fast spin echo with fat-suppression (fFSE). Twenty-seven patients with pelvic disease were examined. EPI images were obtained using 8 shots with breath-holding (bhEPI) and 16 shots without breath-holding (bEPI), while the FSE sequence was fat-suppressed respiratory-triggered FSE. Signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR) and contrast to uterus or ovary (Contrast) were compared between EPI and FSE images. Identification of uterus, ovary, and tumors was carried out simultaneously. In SNR, CNR, and Contrast, EPI could not provide image quality superior to that of fFSE. Moreover, on EPI images, identification of uterus, ovary, and tumors was judged to be inferior or equal. In conclusion, multishot EPI cannot replace fFSE sequences in imaging of the female pelvis. However, because EPI has heavily T2-weighted contrast, the EPI sequence can be a valuable adjunct to routine examination. 相似文献
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Galassi W Phuttharak W Hesselink JR Healy JF Dietrich RB Imbesi SG 《AJNR. American journal of neuroradiology》2005,26(3):553-559
BACKGROUND AND PURPOSE: Contrast-enhanced fluid-attenuated inversion recovery (FLAIR) imaging has been reported to have higher sensitivity for detecting leptomeningeal disease compared with contrast-enhanced T1-weighted MR imaging. The purpose of this study was to compare contrast-enhanced T1-weighted MR images with fat suppression to contrast-enhanced FLAIR images to determine which sequence was superior for depicting meningeal disease. METHODS: We reviewed MR images of 24 patients (35 studies) with a variety of meningeal diseases. The MR imaging protocol included contrast-enhanced T1-weighted MR images with fat suppression (FS) and contrast-enhanced fluid-attenuated inversion recovery (FLAIR) images that were reviewed by three neuroradiologists and were assigned a rating of positive, equivocal, or negative for abnormal meningeal enhancement. The two sequences were compared side by side to determine which better depicted meningeal disease. RESULTS: Abnormal meningeal enhancement was positive in 35 contrast-enhanced T1-weighted MR images with FS and in 33 contrast-enhanced FLAIR studies. In the first group, which had the T1-weighted sequence acquired first (21 of 33 studies), contrast-enhanced T1-weighted images with FS showed superior contrast enhancement in 11 studies (52%), inferior contrast enhancement in six studies (29%), and equal contrast enhancement in four studies (19%) compared with the contrast-enhanced FLAIR images. In the second group, which had the FLAIR sequence acquired first (12 of 33), contrast-enhanced T1-weighted images with FS showed superior contrast enhancement in seven studies (58%), inferior contrast enhancement in two studies (17%), and equal contrast enhancement in three studies (25%). CONCLUSION: Contrast-enhanced T1-weighted MR imaging with FS is superior to contrast-enhanced FLAIR imaging in most cases for depicting intracranial meningeal diseases. 相似文献
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Yamamoto S Takano H Motoori K Ueda T Ikeda M Kimura S Uno T Yasuda S Ito H Hara R Isobe K 《The British journal of radiology》2001,74(885):805-810
The aim was to compare fast short time inversion recovery (FSTIR) images and fat suppression, contrast enhanced T(1) weighted (FSCE T1W) spin echo images in the diagnosis of nasopharyngeal carcinoma (NPC). 102 MR studies were obtained with a 1.0 T or a 1.5 T system in 28 patients with NPC. The MR studies comprised both FSTIR and FSCE T1W images. FSTIR and FSCE T1W images were compared for detection of NPC by means of a receiver operating characteristic (ROC) analysis. The areas under the ROC curves of FSTIR and FSCE T1W images showed no statistical difference (0.87 vs 0.87). There was also no statistical difference in the sensitivity, specificity and accuracy of each sequence (0.74 vs 0.77, 0.81 vs 0.77 and 0.79 vs 0.77, respectively). Both sequences had the same performance for detection of NPC. FSTIR is as useful as FSCE T1W images, especially in the detection of recurrent tumours, but without the cost of contrast medium. 相似文献
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T Sugahara Y Korogi Y Ge Y Shigematsu L Liang K Yoshizumi M Kitajima M Takahashi 《AJNR. American journal of neuroradiology》1999,20(8):1554-1559
BACKGROUND AND PURPOSE: The T1-weighted fast spin-echo (T1-FSE) MR imaging sequence is not used routinely, since the speed advantage is not as dramatic as it is in T2-weighted imaging. We evaluated the T1-FSE sequence to determine whether this technique can replace the conventional T1-weighted spin-echo (T1-SE) sequence for routine contrast-enhanced imaging. METHODS: Sixty-nine patients with intracranial enhancing lesions underwent both T1-SE and T1-FSE sequences in a random order after administration of contrast agent. Acquisition time was 55 seconds for the T1-FSE sequence and 2 minutes 38 seconds for the SE sequence. The conspicuity of enhancing lesions, peritumoral edema, and gray-to-white matter contrast as well as motion and flow artifacts were analyzed. Signal-to-noise ratios of enhancing lesions, gray matter, and white matter as well as contrast-to-noise ratios (CNRs) of enhancing lesions, with gray matter with white matter as the standard, were calculated. RESULTS: The conspicuity of enhancing lesions was better on T1-FSE sequences than on T1-SE sequences, although the difference in the CNRs of enhancing lesions did not reach significance. Images obtained with the T1-FSE sequence showed less flow and motion artifacts than did those obtained with the T1-SE sequence. The conspicuity of peritumoral edema and gray-to-white matter contrast was lower on the T1-FSE images than on the T1-SE images. CONCLUSION: The T1-FSE sequence reduces imaging time and has the potential to replace the conventional T1-SE sequence for the evaluation of enhancing lesions in the brain when time is a consideration. 相似文献
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Nakayama Y Yamashita Y Matsuno Y Tang Y Namimoto T Kadota M Mitsuzaki K Abe Y Katahira K Arakawa A Takahashi M 《Journal of computer assisted tomography》2001,25(1):55-60
PURPOSE: The value of the fast half-Fourier single-shot turbo spin echo (HASTE) sequence in T2-weighted MRI of the kidney was evaluated as a substitute for the conventional turbo spin echo (TSE) sequence. METHOD: Forty-five patients with suspected abnormalities of the kidney underwent MRI with a 1.5 T system. Breath-hold HASTE and respiratory-triggered TSE sequences were performed. Qualitative and quantitative analyses were performed for comparison of these sequences. RESULTS: The signal-to-noise ratio (SNR) with HASTE was higher than that with TSE. The lesion-to-kidney contrast-to-noise ratio for solid masses with HASTE was almost equal to that with TSE. For cystic masses, the CNR with HASTE was significantly higher than that with TSE (p < 0.05). Respiratory and chemical shift artifacts were significantly smaller on HASTE than on TSE (p < 0.01). However, the blurring artifact was higher on HASTE than on TSE (p = 0.01). CONCLUSION: The HASTE sequence generates high contrast images and is free of motion and chemical shift artifacts, with much better time efficacy. The sequence provides comparable diagnostic information to TSE sequences. 相似文献