Carotid plaque mechanical heterogeneity and stroke risk: a comprehensive study integrating multi-site viscoelastic analysis and RADS classification

OBJECTIVE: Carotid atherosclerosis is one of the important etiologies of ischemic stroke, and the mechanical properties of plaques play a key role in the mechanisms of stroke occurrence. This study aims to systematically evaluate the viscoelastic characteristics of carotid plaques at different locations (proximal shoulder, base, distal shoulder, overall) and with different echogenicities (hypoechoic, hyperechoic), and to explore their relationship with Plaque-RADS scores. METHODS: This study consecutively enrolled 38 patients with carotid atherosclerosis who visited our hospital from June to August 2025, with a total of 76 plaques analyzed. Multi-site viscoelastic ultrasound shear wave imaging was used to obtain plaque stiffness (kPa), D dispersion coefficient (m/s/kHz), and V viscosity coefficient. RESULTS: The stiffness of the plaque base (0.00, P < 0.001) was significantly higher than that of the proximal shoulder (90.00, P < 0.001), distal shoulder (90.00, P < 0.001), and overall plaque (15.00, P < 0.001). Viscosity was higher in the distal shoulder (4.53, P < 0.001) and overall region (4.91, P < 0.001); there was a significant difference in viscosity between hypoechoic and hyperechoic regions on the short-axis section (P = 0.037). Furthermore, plaques with high Plaque-RADS scores (e.g., category 4b) showed significantly higher values in multiple viscoelastic indicators compared to low-score plaques, especially at the base (D dispersion coefficient: 9.49104, P < 0.05; V viscosity coefficient: 7.55209, P < 0.05) and in hypoechoic regions (7.47948, P < 0.05). CONCLUSION: These exploratory findings suggest that multi-site viscoelastic analysis may provide additional biomechanical information for plaque characterization. However, these results are hypothesis-generating rather than confirmatory. Further validation against histopathology, MRI-based plaque characterization, and prospective clinical outcomes is required before any clinical application can be considered.