Abstract TMP18: Predicting Intracranial Hematoma Formation After IV tPA With MR Permeability Imaging

Abstract

Background: Damage to the blood-brain barrier in stroke patients can be detected using standard MR PWI and is associated with subsequent hemorrhagic transformation. No clear methodology for using the phenomenon to guide clinical management has been put forth. Purpose: To design and test a method for predicting subsequent parenchymal hematoma (PH) formation after IV tPA administration using MR PWI Methods: An analysis was performed on a database of stroke patients provided by the STIR and VISTA Imaging Investigators. 75 patients were identified who had a successfully acquired DWI, PWI, and GRE images prior to IV tPA and also had follow-up imaging to assess for PH. The pre-tPA MRI scans were analyzed looking for permeability deficits by comparing temporal signal changes in severely hypoperfused tissue with tissue in the contralateral hemisphere. Permeability was calculated as T1-related signal change and expressed as a percent of the CBV. Follow-up GRE images were reviewed for evidence of PH. All analysis was done using Matlab software. ROC curves were generated to evaluate the performance of the mean permeability at predicting PH. Results: 44 of the 75 patients were women and the mean ± std of the age was 70±17. The mean NIHSS was 12±9. The mean time from onset to tPA was 147±30 minutes. 9 patients developed PH. The mean permeability of the PH group was 6±3.2% compared to the non-PH group which had a mean permeability of 3.7±3%. The ROC curve is seen in Figure 1. The area under the curve is 0.80. The optimal threshold identified for predicting PH was 4.8% which had a sensitivity of 0.67 and a specificity of 0.87. Conclusions: A method for quantitatively assessing damage to the BBB was successfully designed and tested. The ability of this technique to predict PH was fairly good considering there is currently no other way to predict who will develop PH after being treated in the IV tPA time window. Further analysis is needed to determine if this technique could be used to guide thrombolytic therapy.