Early stroke detection and extent: impact of experience and the role of computed tomography angiography source images

AIM: To test the performance of computed tomography angiography "source images" (CTA-SI) versus unenhanced CT (NCCT) for stroke detection and extent using the Alberta Stroke Programme Early CT Score (ASPECTS), and examine the effect of experience and clinical history. MATERIALS AND METHODS: Studies of 23 consecutive patients presenting within 4.5h were analysed by three reviewers of varying experience. Each reviewer, blinded to clinical information reviewed a random order of NCCT and CTA-SI and documented side of infarct and the ASPECTS. The readings were repeated for CTA-SI with and without clinical information. Performance measures and observer agreement were calculated. Applying an ASPECTS threshold of