Perfusion-weighted magnetic resonance imaging in acute intracerebral hemorrhage at baseline and during the 1st and 2nd week: a longitudinal study.

BACKGROUND AND PURPOSE: Ischemic penumbra has been suggested as a contributing mechanism to secondary neuronal injury in intracerebral hemorrhage (ICH). Preliminary data suggest the presence of perihematomal hypoperfusion within the first hours after acute ICH. Our objective was to elucidate perfusion changes in the perihematomal region over time using magnetic resonance imaging (MRI). METHODS: Two perfusion-weighted MRIs were studied prospectively in 18 ICH patients. All patients had an acute perfusion-weighted MRI within 24 h of the onset of symptoms (time 0); 11 patients had a follow-up study on day 7 (time 1), and 7 patients on days 10-14 (time 2). The region of interest (ROI) was placed over the penumbral area, on high-intensity FLAIR and perfusion overlapping map imaging. Clinical data were assessed at baseline (National Institutes of Health Stroke Scale) and on day 90 (Canadian Scale, modified Rankin Scale). RESULTS: The average hematoma volume was 56 (9-140) ml; 10 were located deeply, and 8 were lobar. When we compared the perfusion changes (mean transit time prolongation) in the perihematomal area (lesion ROI) relative to itself over time, we found significant differences only between times 0 and 2 (p = 0.05). There were also significant differences in mean transit time between the lesion ROI and the contralateral mirror ROI in the baseline study (p = 0.001), with a trend to significance for time 1. CONCLUSIONS: Our data confirm the presence of hypoperfusion around an acute ICH and demonstrate that this change disappears completely after the first week. These data suggest that further evaluation of this feature of acute ICH is warranted, as its confirmation may lead to modifications in the current therapeutic approach.

Compensatory activations in patients with multiple sclerosis during preserved performance on the auditory N-back task.

Recent fMRI studies have suggested that multiple sclerosis (MS) patients show adaptive cortical changes (i.e., compensatory mechanisms) during motor and cognitive tasks to limit the clinical impact of tissue injury. In this study, we investigated the activation pattern during the auditory n-back working memory (WM) paradigm in a group of 17 MS patients and 10 healthy controls with preserved performance in WM tasks. Compared with healthy controls, MS patients showed significantly greater bilateral activation in prefrontal cortex (BA 44), and the insula. These findings were similar to those obtained in previous studies showing that compensatory mechanisms during WM tasks in MS may be based on the use of prefrontal areas adjacent to those involved in the task.