ABSTRACT
During the past decade multidetector CT angiography (CTA) has gained wide clinical acceptance for the non-invasive investigation of the intra-and extracranial vascular system. Its diagnostic value has been proved for a variety of pathological entities such as intracranial aneurysms, cerebral venous thrombosis and carotid steno-occlusive disease.1-3 While with older CT generations the scan range was limited to short segments of brainsupplying vessels, multidetector CTA now yields increased anatomic coverage ranging from the aortic arch to the vertex. Thus, both stenoocclusive lesions within the supra-aortic vasculature and concomitant embolic intracranial branch occlusion can reliably be depicted in a single run.4 The value of CTA in acute stroke has been documented first in two studies, by Knauth5 and Shrier6 and their colleagues, who demonstrated both the intracranial vascular occlusion site and the presence of collateralization indicated by the opacification of arterial branches distal to the obliterating thrombus. A report by Lev et al7 using results from angiography for comparison CTA had 98.4% sensitivity and 98.1% specificity for the detection of acute intracranial vascular occlusion, making it an ideal measure for the identification of vascular lesions involved in the development of stroke. Further studies from this group have shown that the incorporation of CTA findings into the admission clinical and neuroradiological work-up of stroke could significantly improve the diagnostic accuracy in differentiating patients with moderate from those with large brain volume at risk.8
