Prediction Of Hemorrhagic Transformation After Intravenous Thrombolysis Based On T2~*-Based Permeability MR Imaging

Background And PurposeImproved prediction of hemorrhagic transformation (HT) would assist clinical decision-making in acute ischemic stroke (AIS). Recent studies have suggested that the permeability metric%Recovery (%R) can indicate blood-brain barrier (BBB) disruption. We proposed to verify the relationship between%Recovery and hemorrhagic transformation after intravenous thrombolysis (IVT) for acute ischemic stroke patients and then assessed the optimal threshold of%Recovery value to predict hemorrhagic transformation, as a potential decision-making aid for reperfusion therapy.Materials And MethodsWe conducted a continuously prospective study including acute ischemic stroke patients, who signed a Informed Consent to receive intravenous thrombolysis in our hospital, from June2009through September2014. We defined ROI as the baseline DWI lesion on every slice and measured its volume. We subsequently transposed ROI to the equivalent%Recovery maps. The slice with the most severe abnormality was chosen for%Recovery. The minimum value of%Recovery was measured and the mean value of%Recovery for all slices within ROI and their contralateral side were analyzed according to hemorrhagic transformation status at follow-up. Hemorrhagic transformation was assessed on24-hour follow-up MRI as hemorrhagic infarction (HI) or parenchymal hematoma (PH).ResultsOf77patients, mean age was67years old,48male included (62.3%),26patients developed hemorrhagic transformation (4PH). For patients with hemorrhagic transformation, the baseline NIHSS scores were higher (12±6vs8±6, p=0.003), ages were older (72±11vs64±13years, p=0.005), DWI lesion volume was larger{10(5-46) vs3(1-8) ml, p<0.001}, mean%Recovery was lower (42±15vs60±12%, p<0.001), minimum%Recovery was lower (29±16vs53±15%, p<0.001). After multi-variate analysis, mean%Recovery (OR=0.907,95%CI:0.855-0.963, p=0.001) and minimum%Recovery (OR=0.914,95%CI:0.867-0.963, p=0.001) were independent predictors of hemorrhagic transformation. ROC analysis indicated mean%Recovery value threshold of60%with a sensitivity of92.3%and a specificity of58.8%(AUC=0.816,95%CI0.719-0.913, p<0.001) and minimum%Recovery value threshold of43%with a sensitivity of88.5%and a specificity of76.5%(AUC=0.860,95%CI0.769-0.952, p<0.001), for identifying hemorrhagic transformation.ConclusionsFor acute ischemic stroke patients, permeability metric%Recovery may be useful to predict hemorrhagic transformation after intravenous thrombolysis.