POTENTIAL OF CT ANGIOGRAPHY IN ACUTE ISCHEMIC STROKE

To study the ability of CT angiography to show intracranial arterial o cclusion and collateral blood flow in patients with acute stroke. METH ODS: Twenty-one patients with acute nonhemorrhagic stroke were studied prospectively with conventional CT, CT angiography, and digital subtr action angiography. On the basis of CT angiographic findings, two neur oradiologists independently assessed the site of arterial occlusion, t he contrast enhancement in arterial branches beyond the occlusion as a measure of collateral blood supply, and the extent of diminished pare nchymal enhancement; they then predicted the extent of ischemic infarc tion. RESULTS: Both raters correctly assessed all trunk occlusions of the basilar artery (n = 4), the internal carotid artery (n = 4), and t he middle cerebral artery (n = 9). The chance adjusted interrater agre ement was kappa = .78. The assessment of branch occlusions of the midd le cerebral artery was less reliable. The agreement rate in judging th e collateral state in 17 occlusions in the anterior cerebral circulati on was 88%. The size of 21 (62%) of 34 hemispheric infarctions was pre dicted correctly. CONCLUSION: CT angiography quickly and reliably adds important information to conventional CT studies in cases of acute is chemic stroke. It shows the site of occlusion, the length of the occlu ded arterial segment, and the contrast-enhanced arteries beyond the oc clusion as an estimate of collateral blood flow.