Frequency and clinical course of stroke and transient ischemic attack patients with intracranial nonocclusive thrombus on computed tomographic angiography

BACKGROUND AND PURPOSE: We sought to determine the frequency and clinical course of patients with acute ischemic stroke or transient ischemic attack (TIA) who had intracranial nonocclusive thrombus (iNOT) on CT angiography (CTA). METHODS: We retrospectively (June 2002March 2007) reviewed consecutive patients with acute ischemic stroke or TIA who had CTA performed acutely for diagnostic work-up. A neuroradiologist reviewed all cases with potential iNOT. Criteria to diagnose iNOT rather than occlusive thrombus or atherosclerotic stenosis were: (1) residual lumen present and eccentric; (2) nontapering thrombus; (3) smooth and well-defined thrombus margins; and (4) absence of vessel wall calcification. We defined functional independence at discharge as modified Rankin scale score ĝ‰Currency sign2. RESULTS: Of 865 patients, 23 (2.7%) exhibited iNOT on CTA (43% women, mean age 69±14 years, median National Institute of Health Stroke Scale score 3 [range, 023]; median onset-to-CTA time 3.5 hours [range, 0.975]). Four patients (17%) deteriorated clinically during the hospital course and had persistent new focal neurological deficits. All of them were functionally dependent at discharge. All 19 patients (83%) without persistent clinical deterioration (2 patients had recurrent TIAs) were functionally independent at discharge. CONCLUSION: Intracranial nonocclusive thrombus on CTA is relatively uncommon. The majority of patients have a good clinical outcome. However, some patients deteriorate clinically and are functionally dependent at discharge.