Twinkling Artifact in Patients with Urinary Stones

Background/ To determine the usefulness of twinkling artifact in detecting urinary stones by sonography according to stone characteristics and sonographic features.Patients and A prospective study was conducted on 60 urinary stones which had been detected by KUB, IVP or CT scan. First of all, gray scale sonography was performed using 3.5-5 MHz phased array and data including stone size, location and posterior shadow were registered. Then, presence or absence of twinkling artifact and its intensity with respect to different filters (0-3), pulse repetition frequencies (PRF) (244, 1563, and 4864 Hz), and focal zones (at the level of the stone, lower and higher) was assessed using color Doppler sonography. Finally and in the case of artifact presence, spectral Doppler sonographywas performed. For data analysis, χ2 and independent t test was used. The prevalence of twinkling artifact was 78.3%. Artifact presence in a PRF value of 1563 Hz was significantly related to the echo difference between stone and adjacent tissues (p= 0.001). The above findings together with the fact that twinkling artifact was strongly present in more than half the cases, indicates the sufficiency in detecting urinary stones.