Iodinated contrast media and cerebral hemorrhage after intravenous thrombolysis

<p>Background and Purpose: Iodinated contrast is increasingly used in CT perfusion or angiographic examinations in acute stroke. Increased risk of intracranial hemorrhage (ICH) complicating microcatheter contrast injections has recently been reported in the second Interventional Management of Stroke (IMS 2) trial with contrast toxicity potentially contributory.</p> <p>Methods: We reviewed clinical and radiological data on all patients treated with intravenous alteplase at a single center between May 2003 and November 2008.</p> <p>Results: Of 312 patients treated with intravenous alteplase, 69 (22.1%) received intravenous iodinated contrast in volumes between 50 and 150 mL. Incidence of symptomatic ICH defined as per European Cooperative Acute Stroke Study 2 was 16 of 312 (5.1%; 95% CI, 2.7% to 7.6%); among patients not given contrast, it was 12 of 243 (4.9%; 2.2% to 7.7%) compared with 4 of 69 (5.8%; 0.3% to 11.3%) in those given contrast. Incidence of symptomatic ICH defined as per Safe Implementation of Thrombolysis in Stroke-MOnitoring Study (SITS-MOST) criteria was 12 of 312 (3.9%; 1.7% to 6%), 9 of 243 (3.7%; 1.3% to 6%) among those not given contrast, and 3 of 69 (4.4%; 95% CI, -0.5% to 9.2%) among those given contrast. Patients with symptomatic ICH were older, had higher pretreatment National Institutes of Health Stroke Scale, and blood glucose than those without symptomatic ICH. In logistic regression analysis, pretreatment blood glucose was the only significant predictor of symptomatic ICH by either definition (OR, 1.23; 95% CI, 1.03 to 1.48 per mmol/L increment; P=0.024). Contrast administration or dose was not associated with symptomatic ICH.</p> <p>Conclusions: Intravenous iodinated contrast in doses typically required for CT angiography and perfusion imaging was not associated with symptomatic intracranial hemorrhage in patients treated with alteplase.</p&gt

Derivation and evaluation of thresholds for core and tissue at risk of infarction using CT perfusion

Background and purpose: Computed tomography perfusion provides information on tissue viability according to proposed thresholds. We evaluated thresholds for ischemic core and tissue at risk and subsequently tested their accuracy in independent datasets.<p></p> Materials and methods: Tissue at risk was evaluated in patients with persistent arterial occlusions, and ischemic core thresholds in patients with recanalization and major clinical improvement. Scans were randomly allocated to derivation or validation groups for tissue at risk and core analysis. Optimum thresholds using mean transit time (MTT), cerebral blood flow (CBF), cerebral blood volume, and delay time (DT) were assessed.<p></p> Results: Absolute MTT, relative MTT and DT were best derived predictors of tissue at risk with thresholds of ≥7 seconds, ≥125%, and ≥2 seconds respectively. DT ≥ 2 seconds was the best predictor in the validation dataset (95% agreement levels = −44 to +30 mL, Bias = −6.9). Absolute and relative MTT were the best derived predictors of infarct volume in the core group (8 seconds and 125% respectively) but relative CBF of ≤45% performed best in the core validation dataset.<p></p> Conclusion: Time-based perfusion thresholds perform well as predictors of tissue at risk of infarction with DT the best predictor. Relative CBF was the best predictor of ischemic core. Evaluation in larger populations is needed to confirm the performance of tissue viability thresholds.<p></p&gt