Introduction: Animal and in vitro studies have demonstrated histologic iatrogenic endothelial injury after stent-retriever thrombectomy. However, non-contrast vessel wall magnetic resonance imaging (MRI) studies have failed to demonstrate vessel injury. Our prospective study examines iatrogenic endothelial damage after stent-retriever thrombectomy in vivo utilizing high-resolution contrast-enhanced vessel wall MRI (VW-MRI).
Methods: We evaluated 11 patients, including post-thrombectomy and control subjects, on a Signa HDx 3.0-T MRI scanner with an 8-channel head coil. Pre- and post-contrast T1-weighted CUBE vessel wall images and MR angiograms were acquired with attention to the Circle of Willis. Parenchymal imaging included diffusion, susceptibility, and T2 FLAIR-weighted images. The primary endpoint was vessel wall enhancement, as determined by two independent, blinded board-certified neuroradiologists prior to examination of parenchymal imaging. Additional covariates were age, NIHSS, level of occlusion, stroke etiology, devices utilized, number of passes required for thrombectomy, TICI reperfusion score, stroke volume and 90-day mRS.
Results: Post-contrast T1-weighted vessel wall enhancement was detected in the MCA M2 segment in 100%, the M1 segment in 83%, and the ICA in 50% of thrombectomy patients. One patient demonstrated A1 segment ACA enhancement, and was prospectively identified by both radiologists as having undergone ACA thrombectomy due to embolism during MCA thrombectomy (Figure 1). Post-contrast T1-weighted vessel wall enhancement was detected in 0% of control patients.
Conclusions: Our findings suggest that vessel wall injuries incurred during stent-retriever thrombectomy can be detected utilizing contrast-enhanced 3 Tesla VW-MRI. Our results further demonstrate greater endothelial injury when the thrombectomy device is oversized relative to the target vessel. Further studies are needed to evaluate the clinical significance of endothelial injury and differential effects of the device employed.
Patient Care: Our research demonstrates imaging findings that suggest endothelial injury can be detected. If our future projects demonstrate clinical significance in stroke outcomes, the results will affect future device design and neuroprotective agent trials.
Learning Objectives: 1- Understanding the importance of contrast administration in detection of endothelial injury
2- Development of highly specialized protocols for evaluation of endothelial injury
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