Application of the Carotid Plaque-RADS Classification System in Ultrasound: Inter- and Intra-Observer Agreement...

This study represents the first evaluation of the Plaque-RADS (Reporting and Data System) classification system's applicability in carotid ultrasound examinations. It focuses on analyzing inter-observer and intra-observer agreement among physicians of varying experience levels while investigating its learning curve to validate the system's suitability and stability within the ultrasound field.

This single-center study consecutively enrolled 604 carotid ultrasound images from 302 examinees. Three sonographers with varying levels of experience (expert, associate senior physician, and intermediate physician) independently classified all images using the Plaque-RADS system to assess inter-observer agreement. A second assessment was conducted 3 months after the initial evaluation to examine intra-observer agreement. Moreover, learning curves for each physician level were evaluated using 5 consecutive case groups.

Regarding inter-observer agreement, near-perfect agreement was observed between the expert and associate senior physician (κ = 0.804, 95% CI: 0.765-0.842). Agreement between the expert and intermediate physician (κ = 0.754, 95% CI: 0.711-0.793) and between the associate senior and intermediate physician (κ = 0.670, 95% CI: 0.620-0.713) was also statistically significant. Intra-observer agreement demonstrated good stability across 2 assessments for all 3 physicians, with κ values of 0.901 (95% CI: 0.872-0.930) (expert), 0.843 (95% CI: 0.808-0.878) (associate senior physician), and 0.804 (95% CI: 0.766-0.843) (intermediate physician). Learning curve analysis revealed that both associate senior physician and intermediate physician steadily improved their agreement with the expert as case experience increased.

Research findings indicate that the Plaque-RADS classification system demonstrates high applicability in the field of ultrasound. Through training, this system can be effectively utilized by physicians of varying skill levels, providing a reliable tool for standardized assessment of carotid plaque and stroke risk stratification.