Vivek Rai, MD

Yassi N, Parsons MW, Christensen S, Sharma G, Bivard A, Donnan GA, et al. Prediction of Poststroke Hemorrhagic Transformation Using Computed Tomography Perfusion. Stroke 2013.

Intracerebral hemorrhage is a feared complication of thrombolysis that has been shown to be associated with increased mortality. In addition to several clinical risk factors, several MRI based studies have identified predictive parameters for hemorrhagic transformation after thrombolysis such as DWI lesion volume, severe hypoperfusion (High TMax), low CBV and late phase T2* signal loss in perfusion sequences. While MRI parameters seem to be informative, MRI remains a difficult study to obtain during acute phase of stroke. 

Yassi and colleagues sought to identify optimal CT Perfusion parameters for prediction of parenchymal hemorrhage (PH) after stroke in this study on 132 patients of which about half underwent thrombolysis. They report that TMax >14 sec volumes of >5 ml allowed prediction of PH with sensitivity 79% and specificity 68%. The results are in line with similar work with MRI. The study shows that assessment of severely ischemic tissue, which in turn predicts hemorrhagic transformation, is possible with CTP and that TMax may be an optimal parameter for this. 

While this is an important finding that advances our understanding of perfusion studies; the application of the study in clinical setting remains unclear. At present, I will continue to rely on clinical criteria for prediction of hemorrhagic transformation in patients treated with IV thrombolysis. On the other hand, this might be an important parameter to consider in patients undergoing endovascular treatment especially in extended time window.