Purpose:To determine whether admission computed tomography (CT) perfusion-derived permeability-surface area product (PS) maps differ between patients with hemorrhagic acute stroke and those with nonhemorrhagic acute stroke. Materials and Methods:This prospective study was institutional review board approved, and all participants gave written informed consent. Forty-one patients who presented with acute stroke within 3 hours after stroke symptom onset underwent two-phase CT perfusion imaging, which enabled PS measurement. Patients were assigned to groups according to whether they had hemorrhage transformation (HT) at follow-up magnetic resonance (MR) imaging and CT and/or whether they received tissue plasminogen activator (TPA) treatment. Clinical, demographic, and CT perfusion variables were compared between the HT and non-HT patient groups. Associations between PS and HT were tested at univariate and multivariate logistic regression analyses and receiver operating characteristic (ROC) analysis. Results:HT developed in 23 (56%) patients. Patients with HT had higher National Institutes of Health Stroke Scale (NIHSS) scores (P ϭ .005), poorer outcomes (P ϭ .001), and a higher likelihood of having received TPA (P ϭ .005) compared with patients without HT. Baseline blood flow (P ϭ .17) and blood volume (P ϭ .11) defects and extent of flow reduction (P ϭ .27) were comparable between the two groups. The mean PS for the HT group, 0.49 mL ⅐ min Ϫ1 ⅐ (100 g) Ϫ1 , was significantly higher than that for the non-HT group, 0.09 mL ⅐ min Ϫ1 ⅐ (100 g) Ϫ1 (P Ͻ .0001). PS (odds ratio, 3.5; 95% confidence interval [CI]: 1.69, 7.06; P ϭ .0007) and size of hypoattenuating area at nonenhanced admission CT (odds ratio, 0.4; 95% CI: 0.2, 0.7; P ϭ .002) were the only independent variables associated with HT at stepwise multivariate analysis. The mean area under the ROC curve was 0.918 (95% CI: 0.828, 1.00). The PS threshold of 0.23 mL ⅐ min Ϫ1 ⅐ (100 g) Ϫ1 had 77% sensitivity and 94% specificity for detection of HT. Conclusion:Admission PS measurement appears promising for distinguishing patients with acute stroke who are likely from those who are not likely to develop HT.

BACKGROUND AND PURPOSE:Multimodal CT imaging with contrast-enhanced CT angiography (CTA) and CT perfusion (CTP) is increasingly being used to guide emergency management of acute stroke. However, little has been reported about the safety of intravenous contrast administration associated with these studies in the acute stroke population, including cases in which baseline creatinine values are unknown. We investigated the incidence of contrast-induced nephropathy (CIN), defined as a 25% or more increase in baseline creatinine levels within 72 hours of contrast administration and chronic kidney disease in patients receiving CTAϮCTP at our regional stroke center.

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 (Pϭ0.0001) and less likely to be hypertensive at presentation (Pϭ0.0114). Significant hematoma expansion (Ͼ33% increase from baseline volume) occurred in 20% of secondary ICH patients and 28% of PICH patients (Pϭ0.2463). 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.