Evaluation of in-stent restenosis after carotid artery stenting with superb microvascular imaging: initial findings.

Background: Carotid artery stenting (CAS) is an interventional management in preventing ischemic stroke caused by carotid artery stenosis. After the treatment with CAS, in-stent restenosis caused by neointimal hyperplasia may develop.

Purpose: This study aims to obtain a better determination of neointimal hyperplasia using superb microvascular imaging (SMI), which provides a high-quality visualization of the endoluminal lesions, and to compare these results with B-mode and Doppler ultrasound (US).

Material And Methods: A total of 106 patients who underwent CAS in our interventional radiology unit between 2018 and 2020 were retrospectively analyzed. In total, 44 patients whose procedure images and post-procedural follow-up Doppler US and SMI data could be accessed were included.

Results: There were nine patients who had in-stent restenosis. One patient had no velocity increase; however, on SMI the measurements showed in-stent restenosis both in area and diameter. The other eight patients had a stenosis degree in the range of 50%-79% on Doppler US. Five patients had in-stent restenosis, both in Doppler US and SMI, by area and diameter measurements. Two patients underwent digital subtraction angiography (DSA).

Conclusion: We suggest that using SMI with duplex sonography improves detecting neointimal hyperplasia and in-stent restenosis. With SMI, better visualization of the stent lumen may improve the patient selection for DSA.