Computed Tomography Angiography in the Stroke Outcomes and Neuroimaging of Intracranial Atherosclerosis (SONIA) Study

BackgroundThe Stroke Outcomes and Neuroimaging of Intracranial Atherosclerosis (SONIA) study validated noninvasive imaging tests of intracranial atherosclerosis against catheter angiography in a prospective, blinded, multicenter setting. Critical evaluation of transcranial Doppler (TCD) and magnetic resonance angiography in the SONIA study standardized their performance and interpretation. We performed a similar analysis of computed tomography angiography (CTA) for the detection of intracranial stenosis.MethodsMulticenter standardization of image acquisition and blinded, central interpretation of CTA performance were conducted in concert with the Warfarin-Aspirin Symptomatic Intracranial Disease (WASID) trial. Measurements of the intracranial arterial diameter were obtained to derive stenosis values. Correlation with catheter angiography was used to assess CTA performance characteristics.ResultsCTA measurements of intracranial stenosis were obtained in 120 vessel segments, with angiographic correlation in 52. CTA was performed as a noninvasive study prior to conventional angiography. CTA stenoses of 50-99% or a flow gap were identified in 15 of 52 vessel segments, stenoses of