Early Identification of Potentially Salvageable Tissue with MRI-Based Predictive Algorithms after Experimental Ischemic Stroke

• Published in: Journal of cerebral blood flow and metabolism Vol. 33; no. 7; pp. 1075 - 1082
• Main Authors: Bouts, Mark JRJ, Tiebosch, Ivo ACW, van der Toorn, Annette, Viergever, Max A, Wu, Ona, Dijkhuizen, Rick M
• Format: Journal Article
• Language: English
• Published: London, England SAGE Publications 01.07.2013; Sage Publications Ltd; Nature Publishing Group
• Subjects: Algorithms; Animals; Brain - pathology; Brain Ischemia - complications; Brain Ischemia - pathology; Brain Mapping; Diffusion Magnetic Resonance Imaging - methods; Diffusion Magnetic Resonance Imaging - statistics & numerical data; Disease Models, Animal; Early Diagnosis; Image Processing, Computer-Assisted - methods; Image Processing, Computer-Assisted - statistics & numerical data; Infarction, Middle Cerebral Artery - etiology; Infarction, Middle Cerebral Artery - pathology; Linear Models; Male; Original; Predictive Value of Tests; Rats; Rats, Wistar; Stroke - etiology; Stroke - pathology; perfusion imaging; diffusion-weighted imaging; MRI; tissue outcome prediction; ischemic stroke; salvageable tissue
• ISSN: 0271-678X; 1559-7016; 1559-7016
• DOI: 10.1038/jcbfm.2013.51

Individualized stroke treatment decisions can be improved by accurate identification of the extent of salvageable tissue. Magnetic resonance imaging (MRI)-based approaches, including measurement of a ‘perfusion-diffusion mismatch’ and calculation of infarction probability, allow assessment of tissue-at-risk;however, the ability to explicitly depict potentially salvageable tissue remains uncertain. In this study, five predictive algorithms (generalized linear model (GLM), generalized additive model, support vector machine, adaptive boosting, and random forest) were tested in their potency to depict acute cerebral ischemic tissue that can recover after reperfusion. Acute T2-, diffusion-, and perfusion-weighted MRI, and follow-up T2 maps were collected from rats subjected to right-sided middle cerebral artery occlusion without subsequent reperfusion, for training of algorithms (Group I), and with spontaneous (Group II) or thrombolysis-induced reperfusion (Group III), to determine infarction probability-based viability thresholds and prediction accuracies. The infarction probability difference between irreversible—i.e., infarcted after reperfusion— and salvageable tissue injury—i.e., noninfarcted after reperfusion—was largest for GLM (20 ± 7%) with highest accuracy of risk-based identification of acutely ischemic tissue that could recover on subsequent reperfusion (Dice's similarity index = 0.79 ± 0.14). Our study shows that assessment of the heterogeneity of infarction probability with MRI-based algorithms enables estimation of the extent of potentially salvageable tissue after acute ischemic stroke.