The Value of Shadowing and the Twinkling Artifact in the Diagnosis of Ureteral Stones: A Single-center Study

To determine and evaluate the value of shadowing and the twinkling artifact (TA) for the diagnosis of ureteral stones. Related ultrasound images from 117 patients with suspected ureteral stones were consecutively collected with optimized machine settings, confirmed by computed tomography and then retrospectively reviewed by 12 physicians who were classified into 3 groups according to their experience levels: elementary, intermediate, and advanced. The shadowing/TA grades were separately evaluated by all the participating physicians in a blinded manner, and the consistency was verified using Kendall's coefficient of concordance (Kendall's W). Furthermore, the diagnostic performance was compared among the groups stratified by physicians’ clinical experience levels and ureteral stone sizes. Using shadowing/TA as indicators for ureteral stones, Kendall's W for the TA evaluation was higher than that for shadowing among all the participating physicians and subgroups (P