The measurement of MRI lesion load in multiple sclerosis is increasingly being used to evaluate the natural history of the disease and to monitor the efficacy of treatments. If, as might occur in multicentre studies, lesion load is measured by several observers in different patients or by the same observer in serial scans, it would be necessary to utilize a technique which provides results with high inter- and intra-observer agreements. This study was performed to evaluate the intra- and inter-observer agreement of semi-automated lesion volume measurement using thresholding, and to compare them with those obtained using an arbitrary scoring system (ASS) and a quantitative manual tracing method (MTM). Brain MRIs were obtained for 20 clinically definite multiple sclerosis patients and were evaluated independently by three observers. The median intra- and inter-observer agreements were, respectively, 88.5% (range 69.0-96.8%) and 79.0% (range 73.3-98.3%) using the ASS, 95.0% (range 85.1-99.4%) and 93.4% (range 77.3-98.3%) for the MTM, 96.3% (range 94.2-98.9%) and 93.7% (range 83.8-98.3%) for the semi-automated technique. The intra- and inter-observer agreements for the semi-automated technique increased to 98.5% (range 96.3-99.8%) and 96.1% (range 90.5-98.6%) when a consensus in the choice of threshold for lesion segmentation was reached. The intra- and inter-observer agreements were significantly greater for the semi-automated method compared with both the arbitrary scoring and the MTMs. The intra-observer variability for the semi-automated technique was significantly lower (P < 0.0001) than the inter-observer variability obtained using the same technique. These data indicate that it is possible to obtain high intra- and inter-observer agreements using a semi-automatic thresholding technique to quantify lesion volumes in multiple sclerosis. The technique may prove useful in multicentre studies, in which a single observer is still preferable.

MRI findings in primary angiitis of the central nervous system (PACNS) are highly variable, ranging from normal to diffusely abnormal. We describe brain and spinal cord abnormalities in patients with PACNS and changes over time, to provide criteria which could be useful for differential diagnosis. We reviewed six patients, with a final diagnosis of PACNS, who underwent serial contrast-enhanced brain and spinal MRI. Follow-up ranged from 12 to 60 months. Brain MRI showed multiple small abnormalities in all patients, giving high signal on T2-weighted images, focal or diffuse, mainly in deep and subcortical white matter; four patients had both supra- and infratentorial lesions. On the initial MRI, in five patients, almost 90% of the abnormal foci showed contrast enhancement. Virchow-Robin perivascular spaces were enlarged and simultaneously enhancing in four patients. Three patients also had spinal cord abnormalities, in the cervical and thoracic segments in two, and exclusively cervical segment in one. Two patients had brain biopsy-proven PACNS; in the remainder, the diagnosis of PACNS was presumptive, considering similarities in clinical and MRI features and MRI follow-up. On MRI, after steroid and immunosuppressive therapy, a significant decrease in the number and size of the abnormalities, enhancing and nonenhancing and of enhancing perivascular spaces was observed. Simultaneous enhancement of brain and spinal cord lesions and of perivascular spaces, at the onset of the disease, which resolves during follow-up, can therefore suggest PACNS.

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Several studies report the presence of white matter lesions on brain magnetic resonance imaging in patients with migraine. The aim of our study was to detect the entity of white matter T2-hyperintensities in 90 high selected patients affected by migraine with aura, compared to a group of 90 healthy controls. We found no significant difference of incidence of white matter alterations comparing these two groups.