Progress in the identification of unstable carotid artery plaque

Purpose of review: Ischemic stroke remains a leading cause of death and disability worldwide, with carotid atherosclerosis as a major underlying mechanism. For decades, treatment decisions were based primarily on luminal stenosis, overlooking the biological complexity of plaque instability. This review summarizes recent progress in the imaging-based identification and risk stratification of unstable cerebrovascular plaque, emphasizing the transition from geometric to biological evaluation. Recent findings: Advances in CT, MRI, and ultrasound have enabled in vivo visualization of key features associated with plaque vulnerability, including intraplaque hemorrhage, fibrous cap rupture, neovascularization, inflammation, and perivascular fat alterations. Dual-energy and photon-counting CT now provide spectral and spatial information capable of tissue differentiation at submillimeter scales. MRI offers superior soft-tissue characterization, while contrast-enhanced ultrasound reveals microvascular activity and flow dynamics. The recent introduction of standardized interpretative systems, such as Plaque-reporting and data system (RADS), allows integration of multimodal findings into a unified risk framework. Summary: Contemporary imaging has transformed the assessment of carotid atherosclerosis from a static measurement of stenosis into a dynamic, biology-driven discipline. The combination of advanced imaging, quantitative analysis, and emerging molecular and genetic correlates promises to refine individualized risk prediction and guide targeted prevention strategies for cerebrovascular disease.