Magnetisation transfer ratios of contrast-enhancing and nonenhancing lesions in multiple sclerosis

Magnetisation transfer (MT) is a recently introduced technique for assessing the water content of tissues in vivo and its relationship to macromolecules or membranes. It has been suggested that MT could provide indirect evidence of the characteristics of multiple sclerosis (MS) lesions (oedema, demyelination, or gliosis). Our aims were to characterise brain MS lesions and to compare the magnetisation transfer ratio (MTR) values of lesions with different patterns of contrast enhancement. In patients with MS we measured the MTR of 65 gadolinium-enhancing and 292 nonenhancing lesions. Using the equation published by Dousset et al. we studied 29 patients with clinically definite MS and 10 healthy controls. Lesions had significantly lower MT than the normal-appearing white matter of the patients or the normal white matter of healthy controls. There was no difference in the MTR of enhancing and nonenhancing lesions. Enhancement was homogeneous in 45 and ring-like in 20 lesions; MTR values were lower in the latter. These findings are presumably related to the differences in pathological features of enhancing (different amounts of proteins and inflammatory cells, oedema and demyelination) and nonenhancing (gliosis, demyelination and axonal loss) lesions.     

A single focus of probable multiple sclerosis in the cervical spinal cord mimicking a tumour

A case of probable multiple sclerosis (MS) in the cervical cord without brain involvement, mimicking a tumour is reported. The patient had a progressive left Brown-Séquard syndrome. The diagnosis was suggested by MRI. In spite of intensive corticotherapy, the neurological status worsened, in parallel with the radiological findings. Biopsy excluded an intramedullary tumour and supported the diagnosis of MS.     

MR spectroscopy of cervical spinal cord in patients with multiple sclerosis

MR spectroscopy (MRS) of the brain in patients with multiple sclerosis has been well studied. However, in vivo MRS of the spinal cord in patients with MR spectroscopy has not been reported to our knowledge. We performed MRS of normal-appearing cervical spinal cords in multiple sclerosis patients and in healthy controls. N-acetyl aspartate was shown to be reduced within the cervical spinal cord of multiple sclerosis patients when compared with healthy controls. This finding supports axonal loss and damage within even normal-appearing spinal cords of multiple sclerosis patients.An erratum to this article can be found at     

脊髓多发性硬化的MRI诊断

目的：提高对脊我发性硬化ＭＲＩ特征的认识。材料与方法：地１４例脊髓多发性硬化患者进行颈部ＭＲＩ检查。对病变的长度，横断面上病变大小、位置及病变的强化进行评价结果：１４例患者共发现病变３１个。脊髓多发性硬化ＭＲＩ特征性表现为；大多数为矢状位长度小于２个椎体（８７．１％），病变长度大于宽度，病变局部脊髓政党或轻度肿胀。结论：ＭＲＩ不仅可以发现脊髓多发化病变，并且能显示其特征性表现，有助于与其他脊人病变     

Correlating multiple MRI parameters with clinical features: an attempt to define a new strategy in multiple sclerosis

MRI is the most powerful imaging technique in managing patients with suspected or confirmed multiple sclerosis (MS). However, conventional MRI variables show nonspecific abnormalities weakly correlated with clinical progression of the disease. New techniques, now routinely available, offer better characterisation of the pathophysiology. We combined conventional MRI, including lesion load, contrast enhancement and “black holes” with magnetisation transfer and diffusion-weighted imaging and localised proton MR spectroscopy (MRS) to study their relationship with disability, course and duration of MS. The variables that were the most significantly linked to the course of the disease (relapsing remitting versus secondary progressive) were lesion load, mean overall magnetisation transfer ratio and apparent diffusion coefficient (MGADC), the percentage of ADC in (PADCIMD), and out of (PADCOMD) modal distribution, and the ratio N-acetylaspartate and creatine-containing compounds on MRS of the centrum semiovale. MGADC and PADCIMD were the independent factors most related to disability and duration of disease. Combining MRI techniques is clinically relevant and feasible for studies of MS and may be applied to other diseases of the central nervous system. Received: 10 July 2000/Accepted: 12 December 2000     

3.0T临床型MR多发性硬化大鼠脊髓成像的初步研究

目的：探索应用3.0T临床型MR设备进行多发性硬化（MS）大鼠脊髓成像的可行性。方法：用髓鞘少突胶质细胞糖蛋白多肽35-55（MOG35-55）致敏Lewis大鼠制备MS动物模型实验性自身免疫性脑脊髓炎（EAE）大鼠10只,正常对照组大鼠4只。3.0T临床型MR（Siemens Trio Tim）扫描仪配用正交腕关节线圈,行T2W、T1W和Gd-DTPA增强T1W的三维容积扫描,体素0.06-0.08mm3。结果：大鼠脊髓T2WI具有较高的空间分辨率,颈髓、胸髓和腰髓等节段显示清晰。脊髓灰质和白质的对比度较弱。MOG35-55-EAE大鼠病灶出现在颈髓和胸髓,矢状位重组图像显示病灶细节清晰,呈条片状,T2高信号,T1等信号,4个脊髓病灶均未见Gd-DTPA强化。结论：应用3.0T临床型MR扫描仪配备小正交腕关节线圈进行MOG35-55-EAE大鼠脊髓MR成像是可行的,为小动物脊髓疾病的活体体外监测提供了一种能广泛应用的无创性手段。     

Diffusion tensor MR imaging of the cervical spinal cord in patients with multiple sclerosis

Our purpose was to evaluate the ability of diffusion tensor imaging (DTI) to characterize cervical spinal cord white matter (WM) in patients with multiple sclerosis (MS). DTI were obtained in 21 MS patients and 21 control subjects (CS). Regions of interest (ROIs) were placed at C2/3, C3/4, and C4/5 within the right, left, and dorsal (WM) to calculate fractional anisotropy (FA) and the apparent diffusion coefficient (ADC). Measurements in plaques and normal-appearing white matter (NAWM) of MS patients were compared with mean FA and ADC of WM in CS. FA was significantly lower in all regions in MS patients than in CS. ADC was significantly higher in all regions in MS patients than in CS except for in the dorsal WM at C2/3 and the bilateral WM at C4/5. The mean FA was 0.441 for plaques and 0.542 for NAWM, as compared with 0.739 in CS. The mean ADC was 0.810 × 10⁻³ mm²/s for plaques and 0.722 × 10⁻³ mm²/s for NAWM, as compared with 0.640 ×10⁻³ mm²/s for CS. FA and ADC showed significant differences between plaques, NAWM and control WM(P < 0.01).     

High b-value q-space diffusion-weighted MRI of the human cervical spinal cord in vivo: feasibility and application to multiple sclerosis.

Q-space analysis is an alternative analysis technique for diffusion-weighted imaging (DWI) data in which the probability density function (PDF) for molecular diffusion is estimated without the need to assume a Gaussian shape. Although used in the human brain, q-space DWI has not yet been applied to study the human spinal cord in vivo. Here we demonstrate the feasibility of performing q-space imaging in the cervical spinal cord of eight healthy volunteers and four patients with multiple sclerosis. The PDF was computed and water displacement and zero-displacement probability maps were calculated from the width and height of the PDF, respectively. In the dorsal column white matter, q-space contrasts showed a significant (P < 0.01) increase in the width and a decrease in the height of the PDF in lesions, the result of increased diffusion. These q-space contrasts, which are sensitive to the slow diffusion component, exhibited improved detection of abnormal diffusion compared to perpendicular apparent diffusion constant measurements. The conspicuity of lesions compared favorably with magnetization transfer (MT)-weighted images and quantitative CSF-normalized MT measurements. Thus, q-space DWI can be used to study water diffusion in the human spinal cord in vivo and is well suited to assess white matter damage.     

MR spectroscopy (MRS) and magnetisation transfer imaging (MTI), lesion load and clinical scores in early relapsing remitting multiple sclerosis: a combined cross-sectional and longitudinal study

The purpose of this study was to correlate magnetic resonance imaging (MRI)-based lesion load assessment with clinical disability in early relapsing remitting multiple sclerosis (RRMS). Seventeen untreated patients (ten women, seven men; mean age 33.0 ± 7.9 years) with the initial diagnosis of RRMS were included for cross-sectional as well as longitudinal (24 months) clinical and MRI-based assessment in comparison with age-matched healthy controls. Conventional MR sequences, MR spectroscopy (MRS) and magnetisation transfer imaging (MTI) were performed at 1.5 T. Lesion number and volume, MRS and MTI measurements for lesions and normal appearing white matter (NAWM) were correlated to clinical scores [Expanded Disability Status Scale (EDSS), Multiple Sclerosis Functional Composite (MSFC)] for monitoring disease course after treatment initiation (interferon β-1a). MTI and MRS detected changes [magnetisation transfer ratio (MTR), N-acetylaspartate (NAA)/creatine ratio] in NAWM over time. EDSS and lesional MTR increases correlated throughout the disease course. Average MTR of NAWM raised during the study (p < 0.05) and correlated to the MSFC score (r = 0.476, p < 0.001). At study termination, NAA/creatine ratio of NAWM correlated to the MSFC score (p < 0.05). MTI and MRS were useful for initial disease assessment in NAWM. MTI and MRS correlated with clinical scores, indicating potential for monitoring the disease course and gaining new insights into treatment-related effects. J. Bellmann-Strobl, H. Stiepani and J. Wuerfel contributed equally to this work.     

Improved imaging of the spinal cord in multiple sclerosis using three-dimensional fast spin echo

We report assessment of a new three-dimensional fast spin echo (3D FSE) sequence in ten patients with clinically definite multiple sclerosis, comparing it with standard 2D FSE, and in ten normal controls. We saw 29 focal lesions on the 2D images and 53 on the 3D FSE imgages (P = 0.05); none were seen in controls. Lesion length was significantly smaller on the 3D FSE than on to the 2D FSE images (3D: 1.36; 2D 2,0; P = 0.03). This may relate in part to separation into several lesions on the 3D images of confluent abnormal signal seen on 2D and in part to detection of small lesions missed by the thicker 2D FSE slices (3 mm compared to 1.5 mm). The 3D FSE sequence looks promising in improving spinal cord imaging. Received: 1 June 1997 Accepted: 16 December 1997     

The cervical spinal cord in neuromyelitis optica patients: a comparative study with multiple sclerosis using diffusion tensor imaging

Introduction

This study aims to evaluate “in vivo” the integrity of the normal-appearing spinal cord in patients with neuromyelitis optica (NMO), using diffusion tensor MR imaging, comparing to controls and patients with multiple sclerosis (MS).

Materials and methods

We studied 8 patients with NMO and 17 without any neurologic disorder. Also, 32 MS patients were selected. Fractional anisotropy (FA), axial diffusivity (AD), radial diffusivity (RD) and mean diffusivity (MD) were calculated within regions of interest at C2 and C7 levels in the four columns of the spinal cord.

Results

At C2, the FA value was decreased in NMO patients compared to MS and controls in the anterior column. Also in this column, RD value showed increase in NMO compared to MS and to controls. The FA value of the posterior column was decreased in NMO in comparison to controls. At C7, AD value was higher in NMO than in MS in the right column. At the same column, MD values were increased in NMO compared to MS and to controls.

Conclusions

There is extensive NASC damage in NMO patients, including peripheral areas of the cervical spinal cord, affecting the white matter, mainly caused by demyelination. This suggests a new spinal cord lesion pattern in NMO in comparison to MS.     

A diffusion tensor imaging group study of the spinal cord in multiple sclerosis patients with and without T2 spinal cord lesions

Purpose

To examine the T₂‐normal appearing spinal cord of patients with multiple sclerosis (MS) using diffusion tensor imaging.

Materials and Methods

Diffusion tensor images of the spinal cord were acquired from 21 healthy subjects, 11 MS patients with spinal cord lesions, and 10 MS patients without spinal cord lesions on the T₂‐weighted MR images. Different diffusion measures were evaluated using both a region of interest (ROI) ‐based and a diffusion tensor tractography‐based segmentation approach.

Results

It was observed that the FA, the transverse diffusivity λ_?, and the ratio of the longitudinal and transverse diffusivities (λ_∥/λ _?) were significantly lower in the spinal cord of MS patients with spinal cord lesions compared with the control subjects using both the ROI method (P = 0.014, P = 0.028, and P = 0.039, respectively) and the tractography‐based approach (P = 0.006, P = 0.037, and P = 0.012, respectively). For both image analysis methods, the FA and the λ _∥/λ _? values were significantly different between the control group and the MS patient group without T₂ spinal cord lesions (P = 0.013).

Conclusion

Our results suggest that the spinal cord may still be affected by MS, even when lesions are not detected on a conventional MR scan. In addition, we demonstrated that diffusion tensor tractography is a robust tool to analyze the spinal cord of MS patients. J. Magn. Reson. Imaging 2009;30:25–34. © 2009 Wiley‐Liss, Inc.

     

Texture analysis of spinal cord pathology in multiple sclerosis.

Texture analysis was applied to MR images of the spinal cord in an attempt to quantify pathological changes that occur in multiple sclerosis (MS). Texture features quantify macroscopic lesions and also the microscopic abnormalities that may be undetectable using conventional measures of lesion volume and number. Significant differences in texture between normal controls and MS patients were seen. Texture differences were detected between normal controls and relapsing-remitting patients before detectable spinal cord atrophy. There was also significant correlation between texture and disability. The segmentation and texture analysis technique demonstrates intraobserver coefficients of variation ranging from 0. 6-8.2%. Texture analysis has potential as a tool for monitoring changes associated with the development of disability in patients with MS. Reproducibility and sensitivity must be improved to use the technique for serial monitoring in individuals. Magn Reson Med 42:929-935, 1999.     

Application of a B-spline active surface technique to the measurement of cervical cord volume in multiple sclerosis from three-dimensional MR images

PURPOSE: To evaluate the ability of a B-spline active surface technique to detect cervical spinal cord atrophy due to multiple sclerosis (MS) compared with intensity-based contouring. MATERIALS AND METHODS: In a previously reported study, the cervical spinal cords of 28 MS patients and 13 age-matched controls were imaged with a volume-acquired inversion-prepared fast spoiled gradient echo sequence at baseline and after one year. The images were reanalyzed using the B-spline technique and the results compared with the results obtained in the original report using intensity-based contouring. RESULTS: The mean cervical spinal cord volume determined by the active surface programme was 6487 mm(3) in 28 patients compared with 7117 mm(3) in controls (P = 0.002, corrected for age and gender). The patients' cervical spinal cord volumes were associated with expanded disability status scale scores (parameter estimate = -1.21 x 10(-3), r(2) = 0.39, P = 0.001). The patients' cervical spinal cord volumes did not decrease significantly over one year, unlike the mean cervical spinal cord areas at C2/3 calculated using intensity-based contouring. CONCLUSION: The active surface technique can detect cervical spinal cord atrophy due to MS, which has functional significance. However, this methodology is less sensitive at detecting small serial changes compared with the previously reported method.     

Postmortem MRI of the spinal cord in multiple sclerosis

Postmortem magnetic resonance imaging (MRI) of the spinal cord and the brainstem in a patient with multiple sclerosis are compared with the histopathological findings. Abnormal high signal intensity areas on T2-weighted images correspond precisely to demyelinated areas.     

Comparison of MRI sequences for evaluation of multiple sclerosis of the cervical spinal cord at 3 T

Purpose

Debate remains regarding the utility of the traditional STIR (short inversion time recovery) sequence in aiding MRI diagnosis of spinal cord lesions in patients with multiple sclerosis (MS) and this sequence is not included in the current imaging guidelines. A recent study proposed a T1 weighted STIR as a superior alternative to the traditional STIR and T2 fast spin echo (FSE). Thus, the aim of this study was to compare the sensitivity of T2, standard STIR and T1 weighted STIR sequences in the evaluation of MS plaques on our 3 T system.

Methods and materials

A retrospective analysis of patients with multiple sclerosis who presented to our institution over a period of 5 months and who had cervical cord lesions was undertaken. Patients had been examined with our institutional protocol which included T2 FSE, STIR and the recommended T1 STIR. Quantitative analysis of the lesions versus background cord using sample T-tests was performed for each sequence, and comparative analysis of the lesion contrast:background cord ratios of the 3 sequences (using two-way ANOVA tests) was performed.

Results

The T2 sequence was not as sensitive in detecting lesions versus the traditional STIR and T1 weighted STIR, with 10% of lesions not detected using statistical analysis (p < 0.05). The traditional STIR also demonstrated greater contrast ratios than the T2 sequence (p < 0.05) suggesting increased sensitivity. However, the T1 STIR demonstrated even greater contrast ratios than both the traditional STIR and T2 sequences (p < 0.05).

Conclusion

This study confirms earlier findings of the traditional STIRs increased sensitivity versus the T2 sequence. However, the new “T1 weighted STIR” appears to be even more sensitive than both these sequences showing potential promise as an alternative method to monitor demyelinating plaques of MS.     

Upper cervical spinal cord cross-sectional area in relapsing remitting multiple sclerosis: application of a new technique for measuring cross-sectional area on magnetic resonance images

PURPOSE: To measure accurately the upper cervical cord cross-sectional area (CSA) in patients with relapsing remitting multiple sclerosis (RRMS), and normal control subjects, to address the paradox that longitudinal reduction in CSA has been detected in RRMS while reduction compared to controls has not. We hypothesized that a lack of statistical power and/or measurement sensitivity due to partial volume averaging in previous studies contributed to this paradox. MATERIALS AND METHODS: Using a technique that corrects for partial volume averaging, we measured the CSA in 35 normal controls and 35 RRMS patients. We used the total intracranial volume (TICV) to normalize the CSA and therefore reduce the normal variance and improve the statistical power. RESULTS: The mean TICV did not differ between groups. Statistical power analysis indicated that a 5% reduction in CSA in the patients could be detected with an estimated power of 0.74 before normalization and 0.9 after. The mean CSA in the patients was not reduced compared to controls after (P = 0.928) or before (P = 0.881) normalization. CONCLUSION: Using a sensitive analysis method, and apparently appropriate statistical power, we did not detect reduced CSA in RRMS patients. We hypothesize that this may be due to inflammation.     

MRI in multiple sclerosis of the spinal cord: evaluation of fast short-tan inversion-recovery and spin-echo sequences

We compared the sensitivity of T2-weighted spin-echo (FSE) and fast short-tau inversion-recovery (fSTIR) sequences in detection of multiple sclerosis of the spinal cord in 100 consecutive patients with clinically confirmed multiple sclerosis (MS); 86 patients underwent also brain MRI. In all, 310 focal lesions were detected on fSTIR and 212 on T2-weighted FSE, spinal cord lesions were seen better on fSTIR images, with a higher contrast between the lesion and the normal spinal cord. In 24 patients in whom cord plaques were shown with both sequences, the cranial study was normal or inconclusive. Assessment of spinal plaques can be particularly important when MRI of the brain is inconclusive, and in there situations fSTIR can be helpful. Received: 20 October 1999 Accepted: 23 February 2000