Hemorrhagic Transformation of Ischemic Stroke: Prediction with CT Perfusion

Abstract

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.

Hemorrhagic Transformation after Ischemic Stroke in Animals and Humans

“…173 Blood-brain barrier permeability assessed by perfusion CT is also predictive HT. 174 Other MRI measures that predict HT include T2*-permeability MRI, 175 apparent diffusion coefficient, 176 and very low cerebral blood volume. 177 Collateral circulation has also been associated with HT in patients with stroke.…”

Blood-Brain Barrier Permeability Assessed by Perfusion CT Predicts Symptomatic Hemorrhagic Transformation and Malignant Edema in Acute Ischemic Stroke

“…More recently, a promising new approach involving BBBP imaging has been proposed. [15][16][17][18][19][20][21][22] It models the extravasation of a contrast agent from the intravascular space to the extravascular space and can demonstrate elevated BBBP as an indicator of ischemia-induced vascular damage in stroke. BBBP imaging provides a physiologic individualized measurement intimately connected to the underlying pathophysiology of PH-2 (ischemia-induced vascular damage followed by reperfusion) 23 and may, therefore, offer excellent sensitivity and specificity.…”

Decreased Infarct Volume and Intracranial Hemorrhage Associated with Intra-Arterial Nonionic Iso-Osmolar Contrast Material in an MCA Occlusion/Reperfusion Model

“…Contrast deposition during CT perfusion in the acute ischemic setting has been noted to be a marker of subsequent ICH. [1][2][3] It remains unclear whether this is both cause and effect. Lummel et al 4 recently constructed a nexus between hyperattenuated cerebral lesions and IRCM deposition immediately after mechanical revascularization preceded by CTA/CTP, suggesting that early hyperattenuated lesions were IRCM-volume related with a higher risk of secondary HT, but they did not find them necessarily predictive of reduced clinical functional outcome.…”

“…Data identifying CTP IRCM leakage as a predictor of subsequent hemorrhagic transformation (HT) and intracerebral hemorrhage (ICH) have accumulated. [1][2][3] Yet IRCM deposition in the brain as a sequela of IA revascularization in humans is a frequent phenomenon, commonly but not invariably associated with HT. 4 Having identified relevant differences in ICH following IA infusion of nonionic low-osmolar IRCM in a rat reperfusion model, we postulated that potential clinical differences might also exist between low-osmolar and iso-osmolar IRCM with IA infusion.…”