PURPOSE: Twinkling is an artifact seen on color Doppler ultrasound as a rapidly changing mixture of red and blue behind a stationary echogenic structure. We studied the presence or absence of this artifact in ureteral calculi detected on ultrasound and correlated it with clinical parameters. MATERIALS AND METHODS: We evaluated 284 ureteral calculi seen on color Doppler ultrasound. The twinkling artifact was graded as 0 to 2 and correlated with the presence or absence of pain, symptom duration, degree of hydronephrosis and passage of a Glidewire® guidewire across the ureteral calculus during ureterorenoscopy. RESULTS: The presence or absence of twinkling was not associated with the degree of hydronephrosis. Twinkling was absent in 92% of patients with significant pain and grade 2 twinkling was seen in 69.5% without significant pain. Twinkling was dominantly absent in patients with a recent colic episode, while 77% who presented 2 to 15 days after a colic episode had grade 2 twinkling. The guidewire was difficult to pass in cases with absent twinkling compared to those with grade 2 twinkling, in which the guidewire and ureteral catheter crossed the calculus easily. CONCLUSIONS: Absent twinkling is associated with significant pain, a recent colic episode and difficult guidewire passage across the calculus. These findings suggest that absent twinkling implies significant obstruction, while its presence indicates no significant obstruction.
PURPOSE: Twinkling is an artifact seen on color Doppler ultrasound as a rapidly changing mixture of red and blue behind a stationary echogenic structure. We studied the presence or absence of this artifact in ureteral calculi detected on ultrasound and correlated it with clinical parameters. MATERIALS AND METHODS: We evaluated 284 ureteral calculi seen on color Doppler ultrasound. The twinkling artifact was graded as 0 to 2 and correlated with the presence or absence of pain, symptom duration, degree of hydronephrosis and passage of a Glidewire® guidewire across the ureteral calculus during ureterorenoscopy. RESULTS: The presence or absence of twinkling was not associated with the degree of hydronephrosis. Twinkling was absent in 92% of patients with significant pain and grade 2 twinkling was seen in 69.5% without significant pain. Twinkling was dominantly absent in patients with a recent colic episode, while 77% who presented 2 to 15 days after a colic episode had grade 2 twinkling. The guidewire was difficult to pass in cases with absent twinkling compared to those with grade 2 twinkling, in which the guidewire and ureteral catheter crossed the calculus easily. CONCLUSIONS: Absent twinkling is associated with significant pain, a recent colic episode and difficult guidewire passage across the calculus. These findings suggest that absent twinkling implies significant obstruction, while its presence indicates no significant obstruction.