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

Objective: To determine and evaluate the value of shadowing and the twinkling artifact (TA) for the diagnosis of ureteral stones.

Materials And Methods: 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.

Results: 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 <.05). Furthermore, with no difference in specificity at 100%, the sensitivity of the isolated TA was superior to that of shadowing in groups stratified by the physicians' clinical experience levels and stone sizes, respectively (P <.05). However, for the respective comparisons of shadowing and the TA among groups stratified by stone sizes, as ureteral stones became larger, the detection sensitivities all significantly increased (P ≤.001).

Conclusion: Among physicians, subjective evaluation of the TA is more consistent and has better diagnostic sensitivity than that of shadowing for the diagnosis of ureteral stones, and the stone size may play an important role in the detection sensitivity of these 2 indicators.