Effects of subcortical cerebrovascular lesions on cortical hemodynamic parameters assessed by perfusion magnetic resonance imaging

A simultaneous decrease of cerebral blood volume (CBV) and cerebral blood f low (CBF) has been described after subcortical stroke with positron emissio n tomography, However, this imaging modality cannot be applied routinely to stroke patients. Dynamic susceptibility contrast-enhanced MRI techniques ( DSC-MRI) might be interesting in the assessment of these effects. Dynamic T -2-weighted echo planar imaging was used to produce DSC-MR images during an intravenous bolus injection of gadopentetate dimeglumine in 9 patients who experienced a subcortical stroke involving thalamus or basal ganglia and i n 8 control subjects. A series of 50 consecutive images at 1-second interva ls was acquired at the anatomic level of the centrum semiovale quite distan t from the subcortical lesion, rCBF and rCBV were determined over frontal a nd parietal regions of interest and through the entire cortical mantle. DSC -MRI enabled the detection of hemodynamic changes induced by subcortical st roke. Analysis of rCBV and rCBF values showed that the hemodynamic paramete rs were significantly decreased on the affected side. In controls mean rCBF and rCBV values recorded over the whole cortical mantle of each hemisphere showed no significant interhemispheric asymmetry.