MR perfusion imaging reveals regions of hypoperfusion associated with aphasia and neglect

Objective To evaluate diffusion-weighted imaging (DWI) and MR perfusion ima ging (MRPI) as tools for identifying regions of infarct and hypoperfusion a ssociated with aphasia and neglect in hyperacute stroke. Secondary goal: to establish a functional correlate of a radiologically defined "ischemic pen umbra." Methods: Forty subjects underwent DWI, MRPI, and standardized tests for lexical deficits or hemispatial neglect within 24 hours of stroke onse t or progression. Ten patients had repeat DWI, MRPI, and cognitive testing after 3 days tin some cases after reperfusion therapy). Pearson correlation s between error rate on cognitive testing and volume of abnormality on DWI versus MRPI were determined at each time period, and regions of hypoperfusi on corresponding to specific cognitive deficits were identified. Results: E rror rate was more strongly correlated with volume of hypoperfused tissue o n MRPI (r = 0.65 to 0.93; p < 0.01 to p < 0.0003) than with volume of lesio n on DWI (r = 0.54 to 0.75; p = 0.14 to p < 0.01 for dominant and nondomina nt hemisphere stroke, at each time point. Forty-eight percent of aphasic pa tients and 61% of those with hemispatial neglect had either no infarct or o nly small subcortical infarct on DWI, but had focal cortical hypoperfusion. Patients who had successful reperfusion therapy showed resolution of the h ypoperfused territory beyond the infarction on repeat MRPI and showed resol ution of corresponding deficits. Conclusions. MRPI shows regions of hypoper fused cortex associated with lexical deficits or hemispatial neglect, even when DWI shows no infarct or only small subcortical infarct. MRPI-DWI misma tch indicates regions of functionally salvageable tissue.