Brian Marcus, MD

Li Q, Gao X, Yao Z, Feng X, He H, Xue J, et al. Permeability Surface of Deep Middle Cerebral Artery Territory on Computed Tomographic Perfusion Predicts Hemorrhagic Transformation After Stroke. Stroke. 2017

The authors of this study utilized CT perfusion (CTP) to assess blood brain barrier integrity and to help predict which patients are at risk of hemorrhagic transformation after receiving tPA and/or mechanical thrombectomy. They note that patients who have proximal MCA-M1/distal ICA occlusions are at an increased susceptibility of hemorrhagic transformation, particularly in the deep MCA territory supplied by the lenticulostriate arteries. They aimed to explore the relationship and potential risk factors between permeability and hemorrhagic transformation in the deep MCA territory by utilizing CT perfusion imaging.

The authors performed a multisite retrospective study, specifically looking at patients that were found to have a deep MCA territory hemorrhagic transformation at 24 hours (and had received CT perfusion and CT angiography on admission). In their study, they noted that patients with a proximal MCA/distal ICA and poor collateral circulation had increased permeability in the deep MCA territory.

By utilizing CT perfusion, clinicians will have more tools to help determine when to give tPA by being more clear upfront of a patient’s risk of hemorrhagic transformation after thrombolytic therapy. This data appears similar to using an ASPECTS score when determining which patients are safe to undergo mechanical thrombectomy.

There were a few limitations in this study, as noted by the authors. These include a small sample size and a speculated mechanism of blood brain barrier (BBB) breakdown in the deep MCA territory. Overall, the authors suggest that patients with proximal MCA/distal ICA occlusions with poor circulation are at highest risk of BBB permeability, which can be visualized with CT perfusion studies. As more CT perfusion studies are being performed with the increasing numbers of mechanical thrombectomies, we will hopefully have larger sample sizes to help confirm the findings of these authors.