Pseudoprogression can be distinguished from disease progression in cerebral metastases treated with SRS via an interval decrease in relative CBV and K values.

Background & Purpose Patients with acute ischemic stroke (AIS) are at increased risk of developing parenchymal hemorrhage (PH), particularly in the setting of reperfusion therapies. We have developed a predictive model to examine the risk of PH using combined MR perfusion and diffusion parameters, including cerebral blood volume (CBV), apparent diffusion coefficient (ADC), and microvascular permeability (K2). Methods Voxel-based values of CBV, K2, and ADC from the ischemic core were obtained using pre-treatment MRI data from patients enrolled in the Mechanical Retrieval and Recanalization of Stroke Clots Using Embolectomy (MR RESCUE) clinical trial. The associations between PH and extreme values of imaging parameters were assessed in univariate and multivariate analyses. Receiver operating characteristic (ROC) analysis was performed to determine the optimal parameter/s and threshold for predicting PH. Results In 83 patients included in this analysis, 20 developed PH. Univariate analysis showed significantly lower 10th%-CBV and 10th%-ADC values and significantly higher 90th%-K2 values within the infarction core of patients with PH. Using classification tree analysis, the 10th%-CBV at threshold of 0.47 and 90th%-K2 at threshold of 0.28 resulted in overall predictive accuracy of 88.7%, sensitivity of 90.0%, and specificity of 87.3%, which was superior to any individual or combination of other classifiers. Conclusions Our results suggest that combined 10th%-CBV-90th%-K2 is an independent predictor of PH in patients with AIS with diagnostic accuracy superior to individual classifiers alone. This approach may allow risk stratification for patients undergoing reperfusion therapies.