Integrating magnetization transfer imaging and fat suppression T 2WI for predicting the clinical activity of Graves ophthalmopathy / 中华放射学杂志

Objective:To investigate the value of magnetization transfer imaging (MTI) and fat suppression T 2WI (FS-T 2WI) in predicting the clinical activity of Graves ophthalmopathy (GO). Methods:From October 2020 to July 2021, 64 GO patients were prospectively enrolled in the First Affiliated Hospital of Nanjing Medical University. According to the clinical activity score (CAS), the patients were divided into active group (CAS≥3, 39 patients and 78 eyes) and inactive group (CAS<3, 25 patients and 50 eyes). The coronal MTI and FS-T 2WI were scanned for pre-treatment assessment. Magnetization transfer ratio (MTR) of extraocular muscles, and signal intensity ratio (SIR) between extraocular muscles and temporalis were measured, respectively. The independent-sample t-test was used to compare the MTR and SIR between two groups. The correlations between MRI parameters and CAS were analyzed using Spearman correlation analysis. The receiver operating characteristic (ROC) curve was performed to evaluate the value of each and combined parameters for predicting the clinical activity of GO. The DeLong test was used to compare the area under the curve (AUC). Results:The MTR of active group and inactive group were 0.45±0.04 and 0.51±0.04, respectively, the difference was statistically significant ( t=7.62, P<0.001). The SIR were 3.4±0.6 and 2.6±0.5, respectively, and the difference was also statistically significant ( t=-8.20, P<0.001). MTR was negatively correlated with CAS ( r=-0.46, P<0.001), while SIR was positively correlated with CAS ( r=0.63, P<0.001). The AUC of MTR, SIR and the combination of MTR and SIR for predicting the clinical activity of GO were 0.840, 0.845 and 0.905, respectively. The combination of MTR and SIR showed higher performance than MTR or SIR alone, and the differences were statistically significant ( Z=2.61, P=0.009; Z=2.15, P=0.032). Conclusions:The quantitative parameters of MTI and FS-T 2WI, namely MTR and SIR, can be used to evaluate the clinical activity of GO. Integrating MTI and FS-T 2WI can improve the diagnostic efficiency.

Comparison of Three Magnetization Transfer Ratio Parameters for Assessment of Intestinal Fibrosis in Patients with Crohn's Disease

OBJECTIVE: To establish a novel standardized magnetization transfer ratio (MTR) parameter which considers the element of the normal bowel wall and to compare the efficacy of the MTR, normalized MTR, and standardized MTR in evaluating intestinal fibrosis in Crohn's disease (CD).MATERIALS AND METHODS: Abdominal magnetization transfer imaging from 20 consecutive CD patients were analyzed before performing elective operations. MTR parameters were calculated by delineating regions of interest in specified segments on MTR maps. Specimens with pathologically confirmed bowel fibrosis were classified into one of four severity grades. The correlation between MTR parameters and fibrosis score was tested by Spearman's rank correlation. Differences in MTR, normalized MTR, and standardized MTR across diverse histologic fibrosis scores were analyzed using the independent sample t test or the Mann-Whitney U test. The area under the receiver operating characteristic curve (AUC) was computed to test the efficacies of the MTR parameters in differentiating severe intestinal fibrosis from mild-to-moderate fibrosis.RESULTS: Normalized (r = 0.700; p < 0.001) and standardized MTR (r = 0.695; p < 0.001) showed a strong correlation with bowel fibrosis scores, followed by MTR (r = 0.590; p < 0.001). Significant differences in MTR (t = −4.470; p < 0.001), normalized MTR (Z = −5.003; p < 0.001), and standardized MTR (Z = −5.133; p < 0.001) were found between mild-to-moderate and severe bowel fibrosis. Standardized MTR (AUC = 0.895; p < 0.001) had the highest accuracy in differentiating severe bowel fibrosis from mild-to-moderate bowel wall fibrosis, followed by normalized MTR (AUC = 0.885; p < 0.001) and MTR (AUC = 0.798; p < 0.001).CONCLUSION: Standardized MTR is slightly superior to MTR and normalized MTR and therefore may be an optimal parameter for evaluating the severity of intestinal fibrosis in CD.

Study of inhomogeneous magnetization transfer imaging in multiple sclerosis / 中国医学影像技术

Objective: To observe the value of inhomogeneous magnetization transfer (ihMT) imaging in diagnosis of multiple sclerosis (MS). Methods: Totally 18 patients with clinical diagnosed MS and 16 healthy volunteers were enrolled. ihMT imagings were obtained, while magnetic transfer ratio (MTR), quantitative magnetization transfer (qMT) value, inhomogeneous magnetization transfer ratio (ihMTR) and inhomogeneous quantitative magnetization transfer (qihMT) value of MS lesions and normal white mater of volunteers were measured, respectively. ihMT metrics were compared between MS patients and volunteers. Spearman correlation was conducted to analyze the correlation of MTR, qMT, ihMTR and qihMT values and clinical expanded disability status scale (EDSS) for MS patients. Results: MTR, qMT, ihMTR and qihMT of MS patients were significantly lower than those of volunteers (all P<0.001). There was moderate negative correlation between MTR, qMT and EDSS (r=-0.440, -0.572, P=0.004, 0.002), also significant negative correlation between ihMTR, qihMT and EDSS (r=-0.704, -0.739, both P<0.001). Conclusion: ihMTR and qihMT values are sensitive to detect the changes of myelin content and have good correlation with clinical symptoms, therefore having good prospects for clinical application.

Magnetization Transfer Contrast Angiography for Organized Thrombosed Intracranial Aneurysm in TOF MR Angiography: a Case Report

A 66-year-old woman was referred for treatment of incidental detection of two intracranial aneurysms. Time-of-flight MR angiography (TOF MRA) revealed two aneurysms at the M1 segment of the right middle cerebral artery, and clinoid segment of left internal carotid artery, respectively. On digital subtraction angiography, there was a saccular aneurysm on the left internal carotid artery, but the other aneurysm was not detected on the right middle cerebral artery. Based on comprehensive review of imaging findings, organized thrombosed aneurysm was judged as the most likely diagnosis. In the presented report, magnetization transfer (MT) pulse to TOF MRA was used, to differentiate aneurysm-mimicking lesion on TOF MRA. We report that MT technique could be effective in differentiating true aneurysm, from possible T1 high signal artifact on TOF MRA.

The diagnostic value of magnetization transfer MRI for bowel inflammation and fibrosis in Crohn disease / 中华放射学杂志

Objective To assess the diagnostic value of magnetization transfer MRI (MTI) for bowel inflammation and fibrosis in humans with Crohn disease (CD). Methods From July 2014 through April 2017, 31 patients with a confirmed diagnosis of CD were prospectively recruited from the First Affiliated Hospital of Sun Yat Sen University. They were scheduled for elective surgery due to bowel obstruction and other complications, and underwent preoperative MR enterography (MRE) and MTI within 15 days of surgery. All cases had available intestinal specimens identified on MRE and resected bowel segments for region by region matching. All patients underwent breath hold conventional MRE and MTI examinations, and then the magnetization transfer ratios (MTRs) of pathological bowel segments were measured. Using region by region correlation between MTI and surgical specimen, the bowel segments were resected to stain with HE for evaluating bowel inflammation, Masson for bowel fibrosis, and typeⅠcollagen staining for the deposition of typeⅠcollagen within the bowel walls. The histologic sections from the most severe areas were scored as 0 (normal), 1 (mild), 2 (moderate) and 3 (severe). The correlations between MTR and histologic scores were analyzed by using Spearman rank correlation or partial correlation. The differences in MTR among different grades of bowel fibrosis were analyzed by one way ANOVA. The efficacy of MTR for predicting bowel fibrosis was evaluated by receiver operating characteristic curves analysis. The difference in MTRs between purely inflammatory bowel walls and mixed fibrotic and inflammatory bowel walls was analyzed by Student s t test. Results Sixty two resected bowel specimens from 31 patients including 9 purely inflammatory bowel walls and 53 mixed fibrotic and inflammatory bowel walls were obtained in this study. There were significant differences in MTR among non fibrotic [(21.45 ± 2.65)%], mildly [(30.88 ± 6.14)%], moderately [(35.14 ± 4.31)%] and severely [(35.14 ± 4.31)%] fibrotic walls (F=38.397,P<0.01). MTRs strongly correlated with fibrosis scores (r=0.681, P<0.01). High accuracy of MTRs was shown (curve under area=0.905, P<0.01) for differentiating moderately severely fibrotic from non fibrotic and mildly fibrotic bowel walls. Using MTR of 31.50% as a cutoff value, the sensitivity and specificity were 93.6% and 80.0%, respectively. The MTRs of purely inflammatory bowel walls [(21.45 ± 2.65)%] were significantly higher than that of mixed fibrotic and inflammatory [(36.28±5.21)%] bowel walls (t=-13.052,P<0.01). MTRs correlated with the scores of type Ⅰ collagen (r=0.325, P=0.044) but did not correlate with inflammation scores (r=-0.024, P=0.857). Conclusions MTI enables quantitative evaluation of bowel fibrosis in patients with CD and can be used to differentiate purely inflammatory CD from mixed fibrotic and inflammatory CD.

Evaluation of Magnetization Transfer Ratio Imaging by Phase Sensitive Method in Knee Joint / 의학물리

Although MR imaging is generally applicable to depict knee joint deterioration it, is sometimes occurred to mis-read and mis-diagnose the common knee joint diseases. In this study, we employed magnetization transfer ratio (MTR) method to improve the diagnosis of the various knee joint diseases. Spin-echo (SE) T2-weighted images (TR/TE 3,400-3,500/90?100 ms) were obtained in seven cases of knee joint deterioration, FSE T2-weighted images (TR/TE 4,500-5,000/100?108 ms) were obtained in seven cases of knee joint deterioration, gradient-echo (GRE) T2-weighted images (TR/TE 9/4.56/50degrees flip angle, NEX 1) were obtained in 3 cases of knee joint deterioration, In six cases of knee joint deterioration, fat suppression was performed using a T2-weighted short T1/tau inverse recovery (STIR) sequence (TR/TE =2,894-3,215 ms/70 ms, NEX 3, ETL 9). Calculation of MTR for individual pixels was performed on registration of unsaturated and saturated images. After processing to make MTR images, the images were displayed in gray color. For improving diagnosis, three-dimensional isotropic volume images, the MR tristimulus color mapping and the MTR map was employed. MTR images showed diagnostic images quality to assess the patients' pathologies. The intensity difference between MTR images and conventional MRI was seen on the color bar. The profile graph on MTR imaging effect showed a quantitative measure of the relative decrease in signal intensity due to the MT pulse. To diagnose the pathologies of the knee joint, the profile graph data was shown on the image as a small cross. The present study indicated that MTR images in the knee joint were feasible. Investigation of physical change on MTR imaging enables to provide us more insight in the physical and technical basis of MTR imaging. MTR images could be useful for rapid assessment of diseases that we examine unambiguous contrast in MT images of knee disorder patients.

Quantitative Analysis of Magnetization Transfer by Phase Sensitive Method in Knee Disorder

Magnetization Transfer (MT) imaging generates contrast dependent on the phenomenon of magnetization exchange between free water proton and restricted proton in macromolecules. In biological materials in knee, MT or cross-relaxation is commonly modeled using two spin pools identified by their different T2 relaxation times. Two models for cross-relaxation emphasize the role of proton chemical exchange between protons of water and exchangeable protons on macromolecules, as well as through dipole-dipole interaction between the water and macromolecule protons. The most essential tool in medical image manipulation is the ability to adjust the contrast and intensity. Thus, it is desirable to adjust the contrast and intensity of an image interactively in the real time. The proton density (PD) and T2-weighted SE MR images allow the depiction of knee structures and can demonstrate defects and gross morphologic changes. The PD- and T2-weighted images also show the cartilage internal pathology due to the more intermediate signal of the knee joint in these sequences. Suppression of fat extends the dynamic range of tissue contrast, removes chemical shift artifacts, and decreases motion-related ghost artifacts. Like fat saturation, phase sensitive methods are also based on the difference in precession frequencies of water and fat. In this study, phase sensitive methods look at the phase difference that is accumulated in time as a result of Larmor frequency differences rather than using this difference directly. Although how MT work was given with clinical evidence that leads to quantitative model for MT in tissues, the mathematical formalism used to describe the MT effect applies to explaining to evaluate knee disorder, such as anterior cruciate ligament (ACL) tear and meniscal tear. Calculation of the effect of the effect of the MT saturation is given in the magnetization transfer ratio (MTR) which is a quantitative measure of the relative decrease in signal intensity due to the MT pulse.

Age-Related Changes in Conventional and Magnetization Transfer MR Imaging in Elderly People: Comparison with Neurocognitive Performance

OBJECTIVE: This study was designed to compare three different measures of the elderly human brain; the magnetization transfer ratio (MTR) histogram, the percentage of brain parenchymal volume, and the volume of T2 hyperintense areas in terms of correlations with the study subjects' neurocognitive performance. MATERIALS AND METHODS: Thirty-five healthy community-dwelling elderly volunteers aged 60-82 years underwent dual fast spin-echo (FSE) imaging and magnetization transfer imaging. A semi-automated technique was used to generate the MTR histogram, the brain parenchymal volume, and the T2 lesion volume. The subjects' neurocognitive performance was assessed by using the Korean-Mini Mental State Examination (K-MMSE) and additional tests. The peak height of the MTR (PHMTR), the percentage of brain parenchymal volume (PBV), and the normalized T2 lesion volume (T2LV) were compared between the normal group (Z score on the K-MMSE > or = -2, n=23) and the mild cognitive impairment group (Z score on the K-MMSE < -2, n=12), and these parameters were correlated with age and various neurocognitive performance scores. RESULTS: The PHMTR was significantly lower in the cognitively impaired subjects than the PHMTR in the normal subjects (p = 0.005). The PBV scores were lower in the cognitively impaired subjects than in the normal subjects (p = 0.02). The T2LV scores were significantly higher in the cognitively impaired subjects (p = 0.01). An inverse correlation was found between the PHMTR and T2LV (r = -0.747, p < ; 0.001), and also between the PBV and T2LV (r = -0.823, p < ; 0.001). A positive correlation was observed between the PHMTR and the PBV (r = 0.846, p < 0.001). Scores on the various neurocognitive tests were positively correlated with the PHMTR (6 of 7 items) and the PBV (5 of 7 items), and they were negatively correlated with the T2LV (5 of 7 items). CONCLUSION: Our findings of a correlation among the PBV, the T2LV, and the PHMTR suggest that MTR histograms and the PBV and T2LV can be used as a reliable method and valid statistical tool, respectively, for quantifying the total lesion burden in an aging brain.

MR Imaging of Articular Cartilage: Comparison of Magnetization Transfer Contrast and Fat - Suppression inMultiplanar and 3D Gradient-Echo, Spin-Echo, Turbo Spin-Echo Techniques

PURPOSE: The purpose of this study was to evaluate the effects of magnetization transfer contrast(MTC) andfat-suppression(FS) in variable spin-echo and gradient-echo sequences for articular cartilage imaging and todetermine the optimal pulse sequences. MATERIALS AND METHODS: Using variable 7-pulse sequences, the knees of 15pigs were imaged Axial images were obtained using proton density and T2-weighted spin-echo (PDWSE and T2WSE),turbo spin-echo (TSE), multiplanar gradient-echo (MPGR), and 3D steady-state gradient-echo (3DGRE) sequences, andthe same pulse sequences were then repeated using MTC. Also T1-weighted spin-echo(T1WSE) and 3D spoiledgradient-echo(3DSPGR) images of knees were also acquired, and the procedure was repeated using FS. For each knee,a total of 14 axial images were acquired, and using a 6-band scoring system, the visibility of and thevisibilities of the the articular cartilage was analyzed. The visual effect of MTC and FS was scored using a4-band scale. For each image, the signal intensities of articular cartilage, subchondral bone, muscles, and salinewere measured, and signal-to-noise ratios(SNR) and contrast-to-noise ratios(CNR) were also calculated. RESULTS: Visibility of the cartilage was best when 3DSPGR and T1WSE sequences were used. MTC imaging increased the negativecontrast between cartilage and saline, but FS imaging provided more positive contrast. CNR between cartilage andsaline was highest when using TSE with FS(-3 5 1 . 1 +/-15.3), though CNR between cartilage and bone then fell to-1 4 . 7 +/-10.8. In MTC imaging using MPGR showed the greatest increase of negative contrast between cartilage andsaline(CNR change=-74.7); the next highest was when 3DGRE was used(CNR change=-34.3). CNR between cartilage andbone was highest with MPGR(161.9 +/-17.7), but with MTC, the greatest CNR decrease(-81.8) was observed. Thegreatest CNR increase between cartilage and bone was noted in T1WSE with FS. In all scans, FS provided acartilage-only positive contrast image, though the absolute value of CNR was lower than that of MTC imaging. CONCLUSION: The most prominent effects of MTC and FS were seen in MPGR and T1WSE, respectively, though forcartilage, optimal high signal intensity and contrast can be achieved using 3DGRE with MTC, and 3DSPGR with FS.

Comparison of Magnetization Transfer Ratios of Various Cerebral Edemas

PURPOSE: To compare magnetization transfer ratios (MTR) among various cerebral edemas with different pathophysiologic processes. MATERIALS AND METHODS: Cerebral edemas seen on MR images in 45 patients were classified as one of three types: vasogenic (n=22; tumor[n=9], contusion[n=3], hemangioma[n=4], hemorrhage[n=4], others[2]); cytotoxic (n=18; all acute infarction), and interstitial edema (n=5). In all cases, both T2-weighted images with and without magnetization transfer were obtained using off-set pulses of 600Hz. MTRs in each cerebral edema were measured and compared. RESULTS: The mean MTRs of vasogenic edema, cytotoxic edema and interstitial edema were 22 +/- 5%, 26 +/- 4 % and 19 +/- 2%, respectively. There was no statistically significant difference among the three types (p>0.05). CONCLUSION: Mean MTR was highest in cytotoxic edema and lowest in interstitial edema, but the differences were not significant.

Magnetization Transfer Ratio in Head and Neck Lymphadenopathy

PUYPOSE: The purpose of this study was to determine whether the magnetization transfer ratio(MTR) differs between malignant and benign cervical lymphadenopathy. MATERIALS AND METHODS: Magnetization transfer ratios were obtained from 104 lymph nodes of 43 patients. Fifty-five nodes were malignant and 49 were benign. Biopsy or cervical lymph node dissection was performed in 83 nodes, while the remaining 21 were diagnosed clinically or by follow-up imaging studies. Among the 55 malignant nodes, squamous cell carcinomas accounted for 29 cases, lymphomas for 15, undifferentiated carcinomas for four, acute myelogenous leukemia for four, and melanomas for three. The 49 benign nodes comprised 21 cases of reactive hyperplasia, 12 of Kikuchi's disease, nine of acute lymphadenitis, and seven of tuberculous lymphadenitis. All scans were performed using a 1.5T Magnetom Vision(Siemens, Erlangen, Germany) with phased-array or Helmholtz-type neck coil. Scanning was performed with and without magnetization transfer pulse(MT pulse : 11.2 T, 250 Hz band-width, off-set 2.0 KHz) using FLASH 2D sequencing. The region of interest(ROI) for signal intensity(SI) measurements was sampled at the same nodes by keeping the position, shape and size of the ROI constant for the scans before and after the MT pulse was applied. SI measurements were repeated more than three times in each node and the mean value was used to calculate MTR. In this study, however, corrected MTRs(CoMTRs) were used for correction of the effect of background noise produced by magnetic field inhomogeneity. RESULTS: Mean CoMTRs of malignant and benign nodes were 0.33(SD: +/- 0.04) and 0.28(SD: +/- 0.05), respectively. This difference was statistically significant. At CoMTR 0.31, the sensitivity and specificity of malignant nodes were 83% and 75%, respectively. CONCLUSION: A CoMTR of above 0.31 suggests malignant lymphadenopathy. CoMTR is one of the MR criteria which can serve to differentiate between malignant and benign lymphadenopathy.

Magnetization Transfer on T2-weighted Image: Magnetization Transfer Ratios in Normal Brain and CerebralLesions

PURPOSE: To evaluate the magnetization transfer ratio(MTR) of various normal structures and pathologiclesions, as seen on magnetization transfer T2-weighted images (MT+T2WI). MATERIALS AND METHODS: In ten normalvolunteers, T2-weighted images without MT (MT-T2WI) and with MT(MT+T2WI) were obtained. Off-set pulses used inMT+T2WI were 400, 600, 1000, 1500, and 2000Hz. In 60 clinical cases infarction(n=10), brain tumors(n=5), traumatichematomas(n=5), other hematomas(n=3) vascular malformation(n=2) white matter disease(n=2) normal(n=31) andothers(n=2), both MT-T2WI and MT+T2WI images were obtained using an off-set pulse of 600 Hz. In all volunteers andpatients, MTR in various normal brain parenchyma and abnormal areas was measured. RESULT: The MTRs of white andgray matter were 48% and 45% respectively at 400 Hz, 26% and 22% at 600Hz, 12% and 11% of 1000Hz, 10% and 9% 1500HZ, and 9% and 8% at 2000Hz of RF. The MTR of CSF was 43% at 400 Hz of off-resonance RF, while the contrastresolution of T2WI was poor. An off-resonance of 600Hz appeared to be the optimal frequency. In diseased areas,MTRs varied but were usually similar to or lower than those of brain parenchyma. CONCLUSION: The optimaloff-resonance RF on MT+T2WI appears to be 600 Hz for relatively high MTR of brain parenchyma and low MTR of CSF,in which MTRs of white and gray matter were 26% and 22%, respectively, of 600Hz off-set pulse. The MTRs ofcerebral lesions varied and further studies of various cerebral lesions are needed.

Contrast-Enhanced Turbo Spin-Echo(TSE) T1-weighted Imaging: Improved Contrast of Enhancing Lesions

PURPOSE: The purpose of this study was to evaluate the effect of contrast improvement of enhancing brain lesions by inherent magnetization transfer effect in turbo spin-echo (TSE) T1-weighted MR imaging. MATERIALS AND METHODS: Twenty-six enhancing lesions of 19 patients were included in this study. Using a 1.0T superconductive MR unit, contrast-enhanced SE T1-weighted images (TR=600 msec, TE=12 msec, NEX=2, acquisition time=4 min 27sec) and contrast-enhanced TSE T1-weighted images (TR=600 msec, TE=12 msec, NEX=2, acquisition time=1min 44sec) were obtained. Signal intensities at enhancing lesions and adjacent white matter were measured in the same regions of both images. Signal-to-noise ratio (SNR) of enhancing lesions and adjacent white matter, and contrast-to-noise ratio (CNR) and lesion-to-background contrast (LBC) of enhancing lesions were calculated and statistically analysed using the paired t-test. RESULTS: On contrast-enhanced TSE T1-weighted images, SNR of enhancing lesions and adjacent white matter decreased by 18%(p<0.01) and 32% (p<0.01), respectively, compared to contrast-enhanced SET1-weighted images. CNR and LBC of enhancing lesions increased by 16% (p<0.05) and 66% (p<0.01), respectively. CONCLUSION: Due to the proposed inherent magnetization transfer effects in TSE imaging, contrast-enhanced T1-weighted TSE images demonstrated a statistically significant improvement in CNR and LBC, compared to conventional contrast-enhanced T1-weighted SE images, and scan time was much shorter.

Effects of Magnetization Transfer in Gadolinium-Enhanced Brain MR Imaging

PURPOSE: To evaluate the effect of magnetization transfer(MT) in contrast-enhanced brain MR imaging of the various intracranial diseases. MATERIALS AND METHODS: We prospectively studied the effect of MT incontrast-enhanced brain MR imaging 101 patients with a variety of intracranial diseases. In all patients contrast-enhanced T1-weighted(TR/TE = 550/14) SE MR images with and without MT were obtained on a 1.5 Tsuper conducting unit(Magnetom, Siemens). The MT pulse used for MT images was an 8.1 msec(=250 Hz band width) syncpulse, 1000 Hz off-resonance. We randomly divided the patients into two groups : group I and group II. Group I consisted of 54 patients in whom contrast-enhanced images without MT and then images with MT were obtained just ofter the injection of Gd-DTPA(0.1 mmol/kg). In group II(47 patients), contrast-enhanced images with MT and then the images without MT were obtained, considering the delayed-enhancement effect. The effect of MT was assessed visually and quantitatively. For quantitative assessment, contrast to noise ratios(CNR) were calculated in 27 cases with enhancing intracranial tumors larger than 1 cm. We then compared CNRs of contrast-enhanced images with and without MT. The paired t-test was used for statistical analysis. RESULTS: On visual assessment, only11.9%(12/101) of normally enhancing structures and only 20.3%(14/69) of enhancing lesions showed improved enhancement in images with MT. There was however, no case in which the enhancing lesion was seen only in MR image with MT but not in that without MT. On quantitative analysis there was no statistically significant difference between overall images with MT and those without MT(p>0.05). The average CNR of images with MT was higher than that of images without MT in group I, but not in group II. CONCLUSION: MT in contrast-enhanced brain MR imaging resulted in contrast improvement in a limited number(less than approximately 20%) of patients. Routine application of MT images to contrast-enhanced brain MR imaging may be of limited value. Further studies on the clinical usefulness of MT technique with more refined MT pulse are thus needed.