Perfusion computed tomography for the indication of percutaneous transluminal reconstruction for acute stroke

Perfusion computed tomography (CT) was performed in patients with acute-stage stroke to assess the indications for percutaneous transluminal reconstruction (PTR). This study included 59 patients admitted within 8 hours of onset of stroke in whom initial CT demonstrated no ischemic changes. Multiple regions of interest (ROIs) were selected in the ischemic lesions, and the ratios of cerebral blood flow (CBF) and cerebral blood volume (CBV) in the ROIs were calculated and compared to with those in the same location in the opposite hemisphere. The ischemic boundaries for CBF and CBV were analyzed in 29 patients treated conservatively. PTR was performed in 30 patients without visually decreased CBV. Some of the patients with visually evaluated abnormal regional mean transit time, decreased regional CBF, and normal regional CBV developed infarction, but others did not. The statistical analysis for CBF using the mean ROI ratios of each patient was 0.413 +/- 0.272 (mean +/- SD) (median, 0.307) in regions with subsequent infarction and 0.750 +/- 0.221 (0.772) in regions without infarction (P < .005), and that for CBV was 0.837 +/- 0.367 (0.778) in regions with subsequent infarction and 1.137 +/- 0.324 (1.121) in regions without infarction (P < .005). The statistical analysis for CBF using the highest and lowest ROI ratios of each patient was 0.548 +/- 0.342 (0.428) in regions with infarction and 0.584 +/- 0.191 (0.636) in regions without infarction (P = .655), and that for CBV was 0.997 +/- 0.430 (0.927) in regions with infarction and 0.948 +/- 0.182 (0.948) in regions without infarction (P = .606). Four of the 24 patients with recanalization after PTA had poor outcome and a CBV ratio of 0.6-0.8. The present study indicates that the ischemic boundary is approximately 0.5 for regional CBF and 0.9 for regional CBV, providing appropriate indications for PTR. Even a slight decrease in CBV, which may not be detected visually, can affect the outcome, and so the regional CBV must be calculated for the correct diagnosis.