Contrast-enhanced carotid ultrasonography and MRI plaque imaging to identify patients developing in-stent intimal hyperplasia after carotid artery stenting

Aim: In-stent intimal hyperplasia (ISH) observed after carotid artery stenting (CAS) may lead to in-stent restenosis. We aimed to investigate whether contrast-enhanced carotid ultrasonography (CEUS) and magnetic resonance imaging (MRI) plaque imaging prior to CAS are predictive for ISH at 6 months after CAS.Material and method: A total of 14 patients (13 men, 1 woman; mean age, 74.2 years) were prospectively enrolled. CEUS and MRI plaque imaging were performed before CAS. ISH was diagnosed by carotid angiography at 6 months after CAS. Patients were divided into two groups based on the thicknessof ISH and age, risk factors, enhancement in CEUS, MRI plaque imaging and number of replaced stents were compared between groups.Results: Carotid angiography at 6 months after CAS revealed ISH in 10 patients. Plaque enhancement on CEUS was observed in 6 patients, all of whom showed ISH. A significant association was seen between plaque enhancement on CEUS and development of ISH (χ2 test, CEUS enhancement (+) 100% vs. CEUS enhancement (-) 50% p=0.040). Carotid plaques in 12 patients were diagnosed as unstable by MRI plaque imaging. Presence of ISH was significantly associated with unstable plaque diagnosed by MRI plaque imaging (χ2 test, unstable 83% vs. stable 0%; p=0.016).Conclusion: Carotid plaque MRI and CEUS may be useful to predict ISH after CAS.