title: Sonographic twinkling artifact for renal calculus detection: correlation with CT.
abstract: OBJECTIVE
  To retrospectively correlate sonographic color Doppler twinkling artifact within the kidneys with unenhanced computed tomography (CT) in the detection of nephrolithiasis.
  
  
  METHODS
  Institutional review board approval was obtained for this retrospective HIPAA-complaint investigation, and the informed consent requirement was waived. Sonographic imaging reports describing the presence of renal twinkling artifact between January 2008 and September 2009 were identified. Subjects who did not undergo unenhanced abdominal CT within 2 weeks after sonography were excluded. Ultrasound examinations were reviewed by three radiologists working together, and presence, number, location, and size of renal twinkling artifacts were documented by consensus opinion. Sonographic findings were correlated with unenhanced CT (5-mm section width, no overlap) for nephrolithiasis and other causes of twinkling artifact. The number, location, and size of renal calculi at CT were documented.
  
  
  RESULTS
  The presence of sonographic renal twinkling artifact, in general, had a 78% (95% confidence interval: 0.66, 0.90) positive predictive value for nephrolithiasis anywhere in the kidneys at CT. The true-positive rate of twinkling artifact for confirmed calculi at CT was 49% (73 of 148 twinkling foci), while the false-positive rate was 51% (75 of 148 twinkling foci). The overall sensitivity of twinkling artifact for the detection of specific individual renal calculi observed at CT was 55% (95% confidence interval: 0.47, 0.64).
  
  
  CONCLUSIONS
  While renal twinkling artifact is commonly associated with nephrolithiasis, this finding is relatively insensitive in routine clinical practice and has a high false-positive rate when 5-mm unenhanced CT images are used as the reference standard.
  
  
  BACKGROUND
  http://radiology.rsna.org/lookup/suppl/doi:10.1148/radiol.11102128/-/DC1.
authors: Department of Radiology, Section of Pediatric Radiology, C. S. Mott Children's Hospital, University of Michigan Health System, 1500 E Medical Center Dr, Ann Arbor, MI 48109, USA. jonadill@med.umich.edu
authors: Jonathan R
authors: JR
authors: Dillman
authors: Mariam
authors: M
authors: Kappil
authors: William J
authors: WJ
authors: Weadock
authors: Jonathan M
authors: JM
authors: Rubin
authors: Joel F
authors: JF
authors: Platt
authors: Michael A
authors: MA
authors: DiPietro
authors: Ronald O
authors: RO
authors: Bude
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D016477:Artifacts; D005260:Female; D006801:Humans; D007669:Kidney Calculi / Q000000981:diagnostic imaging*; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D012189:Retrospective Studies; D012680:Sensitivity and Specificity; D014057:Tomography, X-Ray Computed; D018615:Ultrasonography, Doppler, Color