Vascular and nonvascular mimics of the CT angiography "Spot Sign" in patients with secondary intracerebral hemorrhage

Background and Purpose - The newly-described computed tomography angiography (CTA) Spot Sign is present in about one third of patients with acute primary intracerebral hemorrhage (PICH) and predicts hematoma expansion. This sign has not been systematically evaluated in patients with secondary causes of ICH, and mimics have not been characterized. The purpose of this study was to assess for the presence of the Spot Sign in secondary ICH and to document potential mimics of the Spot Sign and their distinguishing features. Methods - We performed a retrospective chart review of consecutive patients presenting with ICH to our regional stroke center between January 2002 and May 2007. Ninety-six ICH patients underwent a CT stroke protocol including CTA. CTA documented a secondary cause for hemorrhage in 30 patients (31%). Each patient was assessed for the presence or absence of the CTA Spot Sign or a mimic by 2 blinded neuroradiologists. Clinical and radiological features of PICH and secondary ICH were compared. Results - No patients with secondary ICH had a true CTA Spot Sign, but several Spot Sign mimics were identified including: micro AVM, posterior communicating artery aneurysm, Moya Moya, and neoplasm-associated calcification. The secondary ICH group was younger (P = 0.0001) and less likely to be hypertensive at presentation (P = 0.0114). Significant hematoma expansion (> 33% increase from baseline volume) occurred in 20% of secondary ICH patients and 28% of PICH patients (P = 0.2463). Conclusion - This study describes mimics of the CTA Spot Sign and classifies them as vascular (microAVM, aneurysm, Moya Moya) or nonvascular (tumor and choroid plexus calcification). Evaluation of the noncontrast CT together with the CTA source images is an essential part of the evaluation for the Spot Sign. Vessels entering the hematoma from the periphery are indicative of an underlying vascular lesion. Our findings suggest that the Spot Sign may be rare in secondary ICH and most specific for PICH.