title: Clinical Effectiveness of Prospectively Reported Sonographic Twinkling Artifact for the Diagnosis of Renal Calculus in Patients Without Known Urolithiasis.
abstract: OBJECTIVE
  The purpose of this study was to determine the clinical effectiveness of prospectively reported sonographic twinkling artifact for the diagnosis of renal calculus in patients without known urolithiasis.
  
  
  METHODS
  All ultrasound reports finalized in one health system from June 15, 2011, to June 14, 2014, that contained the words "twinkle" or "twinkling" in reference to suspected renal calculus were identified. Patients with known urolithiasis or lack of a suitable reference standard (unenhanced abdominal CT with ≤ 2.5-mm slice thickness performed ≤ 30 days after ultrasound) were excluded. The sensitivity, specificity, and positive likelihood ratio of sonographic twinkling artifact for the diagnosis of renal calculus were calculated by renal unit and stratified by two additional diagnostic features for calcification (echogenic focus, posterior acoustic shadowing).
  
  
  RESULTS
  Eighty-five patients formed the study population. Isolated sonographic twinkling artifact had sensitivity of 0.78 (82/105), specificity of 0.40 (26/65), and a positive likelihood ratio of 1.30 for the diagnosis of renal calculus. Specificity and positive likelihood ratio improved and sensitivity declined when the following additional diagnostic features were present: sonographic twinkling artifact and echogenic focus (sensitivity, 0.61 [64/105]; specificity, 0.65 [42/65]; positive likelihood ratio, 1.72); sonographic twinkling artifact and posterior acoustic shadowing (sensitivity, 0.31 [33/105]; specificity, 0.95 [62/65]; positive likelihood ratio, 6.81); all three features (sensitivity, 0.31 [33/105]; specificity, 0.95 [62/65]; positive likelihood ratio, 6.81).
  
  
  CONCLUSIONS
  Isolated sonographic twinkling artifact has a high false-positive rate (60%) for the diagnosis of renal calculus in patients without known urolithiasis.
authors.affiliation: 1 Department of Radiology, University of Michigan Health System, 1500 E Medical Center Dr, B2-A209P, Ann Arbor MI, 48109.
authors.forename: William R
authors.initials: WR
authors.lastname: Masch
authors.affiliation: 1 Department of Radiology, University of Michigan Health System, 1500 E Medical Center Dr, B2-A209P, Ann Arbor MI, 48109.|2 Department of Radiology, Division of Abdominal Imaging, University of Michigan Health System, Ann Arbor, MI.
authors.forename: Richard H
authors.initials: RH
authors.lastname: Cohan
authors.affiliation: 1 Department of Radiology, University of Michigan Health System, 1500 E Medical Center Dr, B2-A209P, Ann Arbor MI, 48109.|2 Department of Radiology, Division of Abdominal Imaging, University of Michigan Health System, Ann Arbor, MI.
authors.forename: James H
authors.initials: JH
authors.lastname: Ellis
authors.affiliation: 1 Department of Radiology, University of Michigan Health System, 1500 E Medical Center Dr, B2-A209P, Ann Arbor MI, 48109.|3 Department of Radiology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH.
authors.forename: Jonathan R
authors.initials: JR
authors.lastname: Dillman
authors.affiliation: 1 Department of Radiology, University of Michigan Health System, 1500 E Medical Center Dr, B2-A209P, Ann Arbor MI, 48109.|2 Department of Radiology, Division of Abdominal Imaging, University of Michigan Health System, Ann Arbor, MI.
authors.forename: Jonathan M
authors.initials: JM
authors.lastname: Rubin
authors.affiliation: 1 Department of Radiology, University of Michigan Health System, 1500 E Medical Center Dr, B2-A209P, Ann Arbor MI, 48109.|2 Department of Radiology, Division of Abdominal Imaging, University of Michigan Health System, Ann Arbor, MI.|4 Michigan Radiology Quality Collaborative, Ann Arbor, MI.
authors.forename: Matthew S
authors.initials: MS
authors.lastname: Davenport
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D016477:Artifacts; D002114:Calcinosis / Q000000981:diagnostic imaging*; D005260:Female; D006801:Humans; D007668:Kidney / Q000000981:diagnostic imaging; D007669:Kidney Calculi / Q000000981:diagnostic imaging*; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D016896:Treatment Outcome; D014463:Ultrasonography; D052878:Urolithiasis / Q000000981:diagnostic imaging; D055815:Young Adult
keywords: artifact; calculus; false-positive; twinkling; urolithiasis