Identifying lesion growth with MR imaging in acute ischemic stroke

Purpose: To determine whether different MR diffusion- and perfusion-weighted imaging (DWT and PWI) parameters are important in distinguishing lesion growth from the acute lesion and from oligemia. Materials and Methods: MR DWI and PWI were acquired from thirteen patients. We defined three regions: (i) LESION - intersection of acute and final lesions. (ii) GROWTH - portion of final lesion not part of acute lesion. and (iii) OLIGEMIA - region of perfusion abnormality not part of either the acute or final lesions. We used logistic regression modeling to distinguish GROWTH from LESION and from OLIGEMIA on a voxel-wise basis using DWI- and PWI-based parameters. Final models were selected based on the Wald statistic and validated by cross-validation using the mean (± standard deviation) area under the curve (AUC) from receiver operating characteristic analysis. Results: The final model for differentiating GROWTH from LESION included DWI, the apparent diffusion coefficient (ADC), cerebral blood flow (CBF) and tissue type (AUC = 0.939 ± 0.028). The final model for differentiating GROWTH from OLIGEMIA included DWI, ADC, CBF, and time-to-peak (AUC = 0.793 ± 0.106). Conclusion: Different MR parameters are important in differentiating lesion growth from acute lesion and from oligemia in acute ischemic stroke.