Prediction of Early Neurological Deterioration Using Diffusion- and Perfusion-Weighted Imaging in Hyperacute Middle Cerebral Artery Ischemic Stroke

Abstract

Background and Purpose— Early neurological deterioration (END) occurs in approximately one third of all ischemic stroke patients and is associated with a poor outcome. Our study sought to assess the value of ultra-early MRI in the prediction of END in stroke patients. Methods— Between August 1999 and November 2001, 38 stroke patients with a proven middle cerebral artery (MCA) or intracranial internal carotid artery (ICA) occlusion on MR angiography underwent perfusion-weighted imaging (PWI) and diffusion-weighted imaging (DWI) within 6 hours after onset, and 30 fulfilled all inclusion criteria. Control DWI and MR angiography were performed between days 3 and 5. Cranial CT was performed to rule out hemorrhagic transformation. Vascular risk factors, temperature, blood pressure, glycemia, and blood count were assessed on admission. National Institutes of Health Stroke Scale (NIHSS) scores were obtained at baseline and at 6, 12, 24, and 48 hours. At the same time points, transcranial Doppler (TCD) examinations were conducted to assess arterial recanalization. END was defined as an increase in the NIHSS score >4. A logistic regression model was applied to detect independent predictors of END. The Kruskal-Wallis test was used to evaluate the relationship between infarct growth and duration of vessel occlusion. Results— Initial MR angiography showed an occlusion of intracranial ICA in 7 patients (23.3%), of proximal MCA in 14 (46.6%), and of distal MCA in the remaining 9 (30%). A PWI-DWI mismatch >20% was observed in 28 patients (93.3%). END occurred in 7 patients (23.3%). Baseline NIHSS score ( P =0.05), proximal site of occlusion ( P =0.002), initial DWI ( P =0.002) and PWI ( P =0.003) volumes, and reduced PWI-DWI mismatch ( P =0.038) were associated with END in the univariate analysis. Only hyperacute DWI volume remained as a predictor of END when a logistic regression model was applied (odds ratio, 11.5; 95% CI, 2.31 to 57.10; P =0.0028). A receiver operator characteristic curve identified a cutoff point of DWI >89 cm 3 (sensitivity, 85.7%; specificity, 95.7%) to predict END. A graded response was seen in DWI lesion expansion in relation to duration of arterial occlusion ( P =0.017). Conclusions— Ultra-early DWI is a powerful predictor of END after MCA or intracranial ICA occlusion.