Prediction of poststroke hemorrhagic transformation using computed tomography perfusion

Background and purpose: Intracerebral hemorrhage is a serious potential complication of stroke thrombolysis. We investigated the optimal computed tomography perfusion (CTP) parameter to predict cerebral parenchymal hematoma (PH) in acute ischemic stroke.

Methods: Patients with hyperacute ischemic stroke had whole-brain CTP and follow-up computed tomography/MRI to identify hemorrhagic transformation. The association of the 3 parameters relative cerebral blood flow, relative cerebral blood volume, and time to maximum (Tmax) with PH was examined using receiver operating characteristic analysis and multivariate logistic regression.

Results: Of 132 patients, 70 were treated with thrombolysis, and 14 (10.6%) developed PH on follow-up imaging. Baseline National Institutes of Health Stroke Scale score (P=0.033) and thrombolysis (P=0.003) were both predictive of PH. Receiver operating characteristic analysis revealed that Tmax>14 s (area under the curve=0.748; P=0.002) and relative cerebral blood flow <30% of contralateral mean (area under the curve=0.689, P=0.021) were the optimal thresholds, and the Bayesian information criterion (+2.6) indicated that Tmax was more strongly associated with PH than relative cerebral blood flow. Tmax >14 s volumes of >5 mL allowed prediction of PH with sensitivity of 79%, specificity of 68%, and negative likelihood ratio of 3.16. Tmax>14 s volume and thrombolysis were both independently predictive of PH in a multivariate logistic regression model (P<0.05).

Conclusions: Tmax >14 s was the CTP parameter most strongly associated with PH. This outperformed relative cerebral blood flow <30%, which closely equates to CTP estimates of ischemic core volume. Although ischemic core volume on CTP is useful in the pretreatment prediction of PH, severe hypoperfusion on Tmax is more strongly associated and may allow better prediction of the likely anatomic location of hemorrhage.