Carotid Artery Ultrasonography for Plaque Detection

Carotid artery ultrasonography was performed using a B-mode ultrasound system (EPIQ7 or HD7XE, Philips, Amsterdam, Netherlands) with a linear array transducer (7.5–12 MHz). The examination included bilateral longitudinal and transverse scans of the distal segments of the common carotid artery, the bifurcation segments of the common carotid artery, and the proximal segments of the internal and external carotid arteries. We measured the intima-media thickness (IMT) and plaque formation in the wall of the eight segments of vessels mentioned above. The presence of plaque was defined as one of the following: IMT ≥ 1.5 mm, a focal structure (≥0.5 mm) protruding into the arterial lumen, or the surrounding IMT ≥ 50% (Collaborators, 2017 (link); Dong et al., 2019 (link)).
Carotid plaque was defined as the development of at least one plaque in the eight previously plaque-free arterial segments during reexamination in 2018. To test for inter-observer reliability, plaque measurements in 25 patients were repeated after 1 week by two independent technicians and the results showed high reliability (intraclass correlation coefficients were 0.94).