Reliability of a Standardized Ultrasound Protocol for the Diagnosis of Thoracic Outlet Syndrome

Abstract

Purpose Arterial thoracic outlet syndrome (aTOS) is a rare condition, but if undiagnosed, it can have serious consequences for affected patients, up to and including limb loss. Ultrasound could be used here as a widely available method for screening, but it is said to have very high investigator dependence. The fact that ultrasound can be used safely for diagnostic purposes has already been demonstrated. The aim of this study was to evaluate the repeatability of a standardized examination for the diagnosis of aTOS. Material and Methods We recruited inpatients with high-grade suspected arterial thoracic outlet syndrome who were evaluated for invasive therapy at our TOS center. Routine diagnostics were performed according to clinic standards. In addition, 2 sonographers, one highly experienced and one less experienced, performed ultrasound diagnosis according to a standardized protocol. Image acquisition and interpretation were performed independently, and sonographers were mutually blinded. For analysis, the experienced sonographer served as a reference. Agreement between assessors was analyzed using concordance analysis. Results 51 consecutive patients (67% female) aged 39.3±13.0 years were included within 11 months. The standardized ultrasound protocol could be performed in all patients. The prevalence of TOS was high (79.4%; CI: 71.4-87.3%) in our cohort. Ultrasound inter-rater agreement using the standardized protocol was very good at 0.820 (CI: 0.624-1.000). Conclusion Ultrasound diagnosis of TOS using a standardized protocol can be performed effectively and shows a high agreement between 2 sonographers.