Clodoaldo Pereira

A spinal cord MRI study of benign and secondary progressive multiple sclerosis

This study was performed to achieve a better definition of the nature of the disability in multiple sclerosis (MS). Axial spinal cord magnetic resonance imaging (MRI) at C5 was obtained in 15 patients with benign MS, 17 patients with secondary progressive MS and 10 healthy controls. Patients with secondary progressive MS had smaller spinal cord cross-sectional area (P = 0.01) and transverse diameter (P = 0.006) than patients with benign MS. The degree of disability was inversely correlated with both the cross-sectional area (r = −0.6,P = 0.0018) and transverse diameter (r = −0.5,P = 0.0032) of the cord. Spinal cord atrophy was found in 7 (41%) patients with secondary progressive MS and in 2 (13%) with benign MS. These findings suggest that destructive pathology within MS lesions might play a relevant role in the development of disability in MS.

Quantitative volumetric analysis of brain magnetic resonance imaging from patients with multiple sclerosis.

We compared the volumes of the brain as a whole and of different cerebral structures from patients with multiple sclerosis (MS) and normal subjects. In the patients, we also correlated brain volumes with T2 and T1 lesion loads and disability. A magnetization-prepared rapid acquisition gradient echo (MP RAGE) sequence with subsequent reconstruction of axial 1-mm thick slices and a dual-echo sequence were obtained in 15 patients with relapsing-remitting or secondary progressive MS and 15 sex-, age-, height- and weight-matched normal subjects. The brains and the different cerebral structures studied (cerebral hemispheres, cerebellum and brainstem) were segmented manually by a single observer on the 1-mm MP RAGE scans. The hyperintense lesion volumes seen on dual-echo scans and the hypointense lesion volumes seen on the 1-mm MP RAGE scans were measured using a semi-automated segmentation technique based on local thresholding. Compared to the normal volunteers, patients had significantly lower cerebral (P = 0.008), hemispheric (P = 0.01) and brainstem (P = 0.03) volumes. Cerebral atrophy was detected in seven (47%) MS patients. Patients with brainstem signs had significantly lower mean brainstem volume than the others (P = 0.04). No significant correlations were found between the cerebral volumes and the EDSS scores, the hyperintense lesion volumes and the hypointense lesion volumes. We conclude that cerebral atrophy is a relatively frequent finding in MS, but its relationship with physical disability is modest.

A longitudinal magnetic resonance imaging study of the cervical cord in multiple sclerosis.

This study was performed to evaluate the correlation between changes of crosssectional cord area and disability in multiple sclerosis. Axial magnetic resonance images at the C‐5 spinal level were obtained at entry and 12 months later for 29 patients with clinically definite multiple sclerosis. The degree of disability was inversely correlated at entry and follow‐up with the crosssectional area and the transverse diameter of the spinal cord. In addition, changes in disability correlated inversely with changes in cross‐sectional area (r = ‐0.4, p = 0.04). These findings suggest that cross‐sectional cord area at C‐5 might be a useful marker of disease evolution.

A longitudinal study comparing the sensitivity of CSE and RARE sequences in detecting new multiple sclerosis lesions.

In this longitudinal study, we evaluated the sensitivities of dual-echo, conventional spin-echo (CSE), and rapid-acquisition relaxation-enhanced (RARE) scans for detecting the appearance of new lesions in multiple sclerosis (MS). Dual echo, CSE, and RARE scans were obtained on four occasions each separated by 28 days from five patients with relapsing-remitting MS using a 1.5-Tesla machine. A total of 44 new lesions were detected by the two sequences. Thirty-five lesions were seen on both sequences, three only on CSE and six only on FSE. This study indicates that CSE may be substituted by RARE when monitoring short-term disease activity in MS.

The effect of cross-talk on MRI lesion numbers and volumes in multiple sclerosis using conventional and turbo spin-echo

We measured and compared lesion numbers and volumes present on brain magnetic resonance imaging (MRI) scans of patients with multiple sclerosis (MS) acquired with contiguous (scheme A) and interleaved (scheme B) slice acquisition, to evaluate whether there was a gain in sensitivity using the second pattern of acquisition and whether this counterbalanced the doubled acquisition time. Conventional spin-echo (CSE) sequences were performed for eight patient and turbo spin-echo (TSE) sequences for ten. Acquisition scheme B detected 3.8% more lesions than acquisition scheme A (the increase was 3. 1% for CSE and 4.5% for TSE). These differences were not statistically significant. No significant difference in lesion numbers was found when different lesion locations were also considered. Lesion volumes were significantly higher when scheme B was used (P=0.024). This was due to higher lesion volumes on TSE images (P=0.006), especially on even-numbered slices (P=0.008). Inter-slice cross-talk has a negligible effect on lesion numbers and volume estimates in MS for CSE sequence, whilst it cannot be neglected when TSE sequences are used to measure MS lesion volume.

Serial Contrast-enhanced Mr in Patients with Multiple Sclerosis and Varying Levels of Disability

PURPOSE To compare the rates of enhancement and changes in lesion burden in patients with multiple sclerosis (MS) and varying levels of disability. METHODS Monthly enhanced MR images of the brain were obtained for 6 months from seven patients with mildly disabling relapsing-remitting MS and from seven patients with secondary progressive MS and severe disability. At entry and 1 year later, two unenhanced T2-weighted images of the brain were also obtained. RESULTS Despite the fact that both groups had clinically active disease and had similar increases in unenhanced MR lesion load, the total number of enhancing lesions was 239 in patients with relapsing-remitting MS (42 on the baseline images, 151 new and 46 persistent during follow-up) (average number of lesions per patient per year was 68) and 21 in those with secondary progressive MS (five on the baseline images, 13 new, and three persistent during follow-up) (average number of lesions per patients per year was seven). CONCLUSION Our data indicate that the rate of enhancement significantly decreases in the more advanced phases of MS. This is important when planning clinical trials, and suggests that mechanisms underlying lesion formation might be dissimilar in different MS patient groups.