We compared MRI criteria used to predict conversion of suspected multiple sclerosis to clinically definite multiple sclerosis. Seventy-four patients with clinically isolated neurological symptoms suggestive of multiple sclerosis were studied with MRI. Logistic regression analysis was used to remove redundant information, and a diagnostic model was built after each MRI parameter was dichotomized according to maximum accuracy using receiver operating characteristic analysis. Clinically definite multiple sclerosis developed in 33 patients (prevalence 45%). The optimum cut-off point (number of lesions) was one for most MRI criteria (including gadolinium-enhancement and juxta-cortical lesions), but three for periventricular lesions, and nine for the total number of T2-lesions. Only gadolinium-enhancement and juxta-cortical lesions provided independent information. A final model which, in addition, included infratentorial and periventricular lesions, had an accuracy of 80%, and having more abnormal criteria, predicted conversion to clinically definite multiple sclerosis strongly. The model performed better than the criteria of Paty et al. (Neurology 1988; 38: 180-5) and of Fazekas et al. (Neurology 1988; 38: 1822-5). We concluded that a four-parameter dichotomized MRI model including gadolinium-enhancement, juxtacortical, infratentorial and periventricular lesions best predicts conversion to clinically definite multiple sclerosis.

Background and Purpose-Because the long-term security of endovascular treatments remains uncertain, a follow-up study of the patients treated in the International Subarachnoid Aneurysm Trial was performed to compare the frequency, timing, and consequences of aneurysm recurrence. Methods-Patient data were reclassified by actual treatment performed. Aneurysm and patient characteristics, including occlusion grades, time and type of retreatment, and clinical outcomes, were compared. The relationship between these variables and late retreatment as a surrogate for recurrence was analyzed by means of the Cox proportional hazards model. Results-Retreatment was performed in 191 of 1096 (17.4%) patients after primary endovascular coiling (EVT) and in 39 of 1012 patients (3.8%) after neurosurgical clipping. After EVT, 97 (8.8%) patients were retreated early and 94 (9.0%) late, 7 (0.6%) after rebleeding and 87 (8.3%) without. The mean time to late retreatment was 20.7 months. After neurosurgical clipping, 30 (2.9%) patients were retreated early and 9 (0.85%) late, 3 (0.3%) after rebleeding and 6 (0.6%) without. The mean time to late retreatment was 5.7 months. The hazard ratio (HR) for retreatment after EVT was 6.9 (95% CIϭ3.4 to 14.1) after adjustment for age (Pϭ0.001, HRϭ0.97, 95% CIϭ0.95 to 0.98), lumen size (Pϭ0.006, HRϭ1.1, 95% CIϭ1.03 to 1.18), and incomplete occlusion (PϽ0.001, HRϭ7.6, 95% CIϭ3.3 to 17.5). Conclusions-Late retreatment was 6.9 times more likely after EVT. Younger age, larger lumen size, and incomplete occlusion were risk factors for late retreatment after EVT. After neurosurgical clipping, retreatments were earlier; whereas EVT retreatments continued to be performed throughout the follow-up period. Short-term follow-up imaging is therefore insufficient to detect recurrences after EVT.

We attempted to define the role of subtle changes in the normal-appearing white matter (NAWM) in the development of disability in multiple sclerosis (MS). Twenty-seven clinically definite MS patients with either relapsing-remitting or chronic-progressive courses and 10 sex- and age-matched controls entered the study. For each patient and control, we studied two NAWM areas in the frontal lobe with magnetization transfer imaging (MTI). For patients, we also calculated the MT ratios (MTRs) for three contiguous areas of NAWM progressively further from "isolated" lesions visible on conventional MRI. Frontal NAWM in MS patients had lower mean MTRs than the frontal white matter of the controls (p = 0.02). MTRs in the NAWM adjacent to isolated lesions increased with distance from them to the cortical gray matter (p = 0.04). This pattern was typical for patients with chronic-progressive MS whose MTRs in the first two regions of NAWM adjacent to lesions were lower than those of the same regions of patients with relapsing-remitting MS. This study confirms that there are alterations in the NAWM of MS patients and suggests that such changes might be relevant to the disability in MS.

To assess the importance of intercenter variations when measuring magnetization transfer ratio (MTR) in the brain, six European centers measured MTR in normal white matter. MTR ranged from 9 to 51 percent units (25 sequences). The effective flip angle of the saturating pulse divided by the pulse repetition time (ENRsat degrees/msec) was a good predictor of MTR (MTR = 3.25 ENRsat).J. Magn. Reson. Imaging 1999; 9:441–446. © 1999 Wiley‐Liss, Inc.

New magnetic resonance (MR) measures considered to be putative workers of demyelination and axonal loss were found to be more closely related to clinical disability than T2-weighted MR imaging (MRI) findings in patients with multiple sclerosis (MS). In this study, we evaluated the reproducibility of such measurements in order to assess their reliability for longitudinal studies in MS. The intra-observer coefficients of variation for repeated measurements did not significantly differ among the MR techniques studied [2.6% for T2-weighted MR, 4.38% for unenhanced T1-weighted MRI, 3.65% for magnetisation transfer imaging (MTI) and 2.28% for spinal cord cross-sectional area at C5]. Our findings suggest that non-conventional MR techniques may be reliable outcome measures for clinical trials in MS.