Sonographic detection of renal and ureteral stones: value of the twinkling sign

Abstract

Purpose:To compare the detection of urinary stones using standard gray scale ultrasound for diagnostic accuracy using the color Doppler "twinkling sign". Materials and Methods: Our study population consisted of forty-one patients who demonstrated at least one urinary stone on unenhanced CT evaluation of the kidneys or ureters. Each patient was evaluated using gray scale ultrasound and color Doppler imaging by an observer who was blinded to the CT results. Results: Seventy-seven stones were present in 41 patients, including 47 intrarenal stones, 5 stones in the renal pelvis, 8 stones at the ureteropelvic junction, 5 ureteral stones and 12 stones at the ureterovesical junction. Based upon gray scale sonography the diagnosis of stone was made with confidence in 66% (51/77) of locations. Based upon Doppler sonography using the twinkling sign, the diagnosis of stone was made with confidence in 97% (75/77) of locations. Clustered ROC analysis demonstrated that the Doppler twinkling sign (Az = 0.99) was significantly better than conventional gray scale criteria (Az = 0.95) for the diagnosis of urinary stones (p = 0.005, two-sided test). Conclusions:The color Doppler twinkling sign improves the detection, confidence and overall accuracy of diagnosis for renal and ureteral stones with minimal loss of specificity.

Value of color doppler ultrasound, kub and urinalysis in diagnosis of renal colic due to ureteral stones

“…Although it was first described many years ago, the diagnostic value of twinkling in renal lithiasis is generally unacknowledged (14,15). In the present study, the gray-scale Ultrasound sensitivity and specificity increased significantly when CDU was used with twinkling, where 99.6% of stones could be located with great confidence which is similar to results of recent studies (5,9). Regarding the echographic identification of ureterolithiasis, there are numerous studies with quite contradictory results and with a very wide range of values, the sensitivity of the method ranging between 19% and 96% (16)(17)(18).…”

“…The twinkling in color Doppler images is an artifact created by a rapidly changing series of colored horizontal bars that appear beyond the reflex surfaces assuming a triangular shape when highly evident (4). Many recent studies have reported and encouraged the use of twinkling sign to improve the accuracy of ultrasound to detect renal and ureteral stones (5). In this retrospective study, we evaluated the use of US (gray-scale and Color Doppler), KUB and urine analysis in diagnosis of renal colic due to ureteral calculi in patients presented to ER.…”

The usefulness of agent emission imaging - high mechanical index ultrasound mode in the diagnosis of urolithiasis: a prospective preliminary study

“…In a study by Korkmaz et al (4) (2) demonstrated similarly high detection rates (184 of 214 calculi, 86%). In their study, Mitterberger et al (8) found that twinkling artifact was superior to gray-scale US (with 66% and 97% detection rates, respectively). However, lower detection rates have also been reported in the literature.…”

El artefacto de centelleo en la caracterización de los cálculos urinarios

“…Ulusan et al han identificado la existencia de una potente relación estadística entre la ausencia/ presencia de sombra acús-tica posterior en la ecografía y el tamaño y densidad de un cálculo detectado mediante TAC sin contraste 17 . Existen asimismo estudios que mencionan la existencia de una estrecha relación entre el artefacto de centelleo y el sombreado acús-tico posterior, así como que el artefacto de centelleo posee un mejor valor diagnóstico respecto a los cálculos renales 18 . A la vista de estos resultados, nuestro estudio podría parecer contradictorio al atribuir un menor valor diagnóstico, o incluso ninguna relevancia a la densidad de los cálculos en relación con el artefacto de centelleo.…”