Carotid Intima-Media Thickness and Plaque Assessment by Trained Medical Residents: Validation and Preliminary Testing of a Training Protocol

Abstract

Training of nonsonographer physicians or staff members is needed to implement carotid intima-media thickness (CIMT) and plaque screening by ultrasound for the assessment of subclinical atherosclerosis. The purpose of this study was to determine the effect of formal training on CIMT assessment and plaque detection by medical residents. A medical resident (R1) was trained using an abbreviated American Society of Echocardiography CIMT protocol. CIMT and plaque assessment by R1 were compared against an expert scanner on 60 subjects using a portable US system. A second medical resident (R2) was then trained on the CIMT protocol focusing on plaque visualization after the results of the first phase of the study were analyzed, and the results were compared against an expert on an additional 10 subjects. In the first phase of the study, a total of 106 images (94% interpretable) were available for CIMT and plaque assessment by both R1 and the expert. CIMT measurements were bioequivalent within the limits ofultrasound resolution, with 88% agreement. Variability on plaque presence was high, with only 53% agreement. R2 and the expert each scanned 10 new subjects twice, from whom 40 images were available for interpretation. R2 demonstrated CIMT agreement (93%) comparable with that observed in phase 1 but with greatly improved plaque agreement (100%). Intraobserver variability during phase 2 for both R2 and the expert was extremely low. Medical residents can undergo rapid training for CIMT measurement and plaque visualization todetect subclinical atherosclerosis compared with an expert.