QUANTITATIVE CEREBRAL BLOOD-FLOW DETERMINATIONS IN ACUTE ISCHEMIC STROKE - RELATIONSHIP TO COMPUTED-TOMOGRAPHY AND ANGIOGRAPHY

Background and Purpose The advent of new modalities to treat acute isc hemic stroke presents the need for accurate, early diagnosis. In acute ischemic stroke, CT scans are frequently normal or reveal only subtle hypodense changes. This study explored the utility and increased sens itivity of xenon-enhanced CT (XeCT) in the diagnosis of acute cerebral ischemia and investigated the relationship between cerebral blood flo w (CBF) measurements and early CT and angiographic findings in acute s troke. Methods The CT scans, XeCT scans, and angiograms of 20 patients who presented within 6 hours of acute anterior circulation ischemic s trokes were analyzed. Results CT scans were abnormal in 11 (55%) of 20 patients. XeCT scans were abnormal in all 20 (100%) patients, showing regions of interest with CBF <20 (mL/100 g per minute) in the symptom atic middle cerebral artery (MCA) territories. The mean CBF in the sym ptomatic MCA territories was significantly lower than that of the asym ptomatic MCA territories (P<.0005). In patients with basal ganglia hyp odensities, the mean symptomatic MCA territory CBF was significantly l ower than that of patients who did not exhibit these early CT findings (P<.05). The mean symptomatic MCA territory CBF in patients with angi ographic M1 occlusions was significantly lower than that of patients w hose infarcts were caused by MCA branch occlusions (P<.01). Conclusion s These results show that XeCT is more sensitive than CT in detecting acute strokes and that CBF measurements correlate with early CT and an giographic findings. XeCT may allow for the hyperacute identification of subsets of patients with acute ischemic events who are less likely to benefit and more likely to derive complications from aggressive str oke therapy.