title: Clinical implications and applications of the twinkling sign in ureteral calculus: a preliminary study.
abstract: OBJECTIVE
  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.
  
  
  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.
authors.affiliation: Chitale Clinic Private, Ltd., Solapur, Maharashtra, India. drgrsharma@gmail.com
authors.forename: Gyanendra
authors.initials: G
authors.lastname: Sharma
authors.forename: Anshu
authors.initials: A
authors.lastname: Sharma
mesh_terms: D000293:Adolescent; D000328:Adult; D016477:Artifacts; D002648:Child; D015331:Cohort Studies; D018450:Disease Progression; D005260:Female; D006801:Humans; D007194:India; D008297:Male; D008875:Middle Aged; D010146:Pain / Q000209:etiology / Q000503:physiopathology*; D010147:Pain Measurement; D011237:Predictive Value of Tests; D011446:Prospective Studies; D012680:Sensitivity and Specificity; D012720:Severity of Illness Index; D018615:Ultrasonography, Doppler, Color / Q000379:methods*; D014514:Ureteral Calculi / Q000175:diagnosis / Q000000981:diagnostic imaging* / Q000628:therapy; D018666:Ureteroscopy / Q000379:methods; D055815:Young Adult