Reliability of hemorrhagic transformation diagnosis in acute ischemic stroke

Background and Purpose Diagnosis of hemorrhagic transformation (HT) could influence the prognosis and the management of acute ischemic stroke. The interobserver reliability of CT-scan HT classification is evaluated in the present study. Methods Fifty 5-day CT scans of patients enrolled in the Multicenter Acute Stroke Trial-Italy (MAST-T) were reviewed independently by two neuroradiologists and one neurologist with CT training. They evaluated the presence and type of intraparenchymal HT (hemorrhagic infarction types I, II, and III and intracerebral hemorrhage) (five-item scale), as well as the presence of intraventricular and/or subarachnoid bleeding according to standardized definitions. Results Agreement for exclusion of HT and intraventricular/subarachnoid bleeding was good between the neuroradiologists (kappa=0.70 and kappa=0.72) and excellent between the neurologist and each neuroradiologist (kappa=0.87 and kappa=0.77, kappa=0.83, and kappa=0.81, respectively). The overall agreement for the five-item HT scale between the two neuroradiologists was good (kappa(W)=0.65) because of discordance over the last three items. Better overall agreement was obtained with a three-item scale: no hemorrhage, petechial type I hemorrhagic infarction, and other HT (type II and type III hemorrhagic infarction and intracerebral hemorrhage) together (kappa(W)=0.82). Conclusions Exclusion of HT is a reliable CT diagnosis when made by neuroradiologists and also by a neurologist with CT training. Five- and three-item scales of HT types showed good to excellent reliability. The validity of the scale for predicting short- and long-term outcome should be evaluated in future studies.