title: Can the degree of hydronephrosis on ultrasound predict kidney stone size?
abstract: OBJECTIVE
  The aim of the study was to determine if the degree of hydronephrosis on focused emergency renal ultrasound correlates with kidney stone size on computed tomography.
  
  
  METHODS
  A retrospective study was performed on all adult patients in the emergency department who had a focused emergency renal ultrasound and ureterolithiasis on noncontrast computed tomography. Severity of hydronephrosis was determined by the performing physician. Ureteral stone size was grouped into 5 mm or less and larger than 5 mm based on likelihood of spontaneous passage.
  
  
  RESULTS
  One hundred seventy-seven ultrasound scans were performed on patients with ureteral calculi. When dichotomized using test characteristic analysis, patients with none or mild hydronephrosis (72.9%) were less likely to have ureteral calculi larger than 5 mm than those with moderate or severe hydronephrosis (12.4% vs 35.4%; P < .001) with a negative predictive value of 0.876 (95% confidence interval, 0.803-0.925).
  
  
  CONCLUSIONS
  Patients with less severe hydronephrosis were less likely to have larger ureteral calculi.
authors.affiliation: Department of Emergency Medicine, Long Island Jewish Medical Center, New Hyde Park, NY 11040, USA. JGoertz@nshs.edu
authors.forename: Jacob K
authors.initials: JK
authors.lastname: Goertz
authors.forename: Seth
authors.initials: S
authors.lastname: Lotterman
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D016009:Chi-Square Distribution; D004635:Emergency Medicine; D004636:Emergency Service, Hospital; D004638:Emergency Treatment; D005260:Female; D006801:Humans; D006869:Hydronephrosis / Q000145:classification / Q000000981:diagnostic imaging* / Q000209:etiology*; D008297:Male; D008875:Middle Aged; D015588:Observer Variation; D011237:Predictive Value of Tests; D012189:Retrospective Studies; D012307:Risk Factors; D012680:Sensitivity and Specificity; D012720:Severity of Illness Index; D014057:Tomography, X-Ray Computed; D014463:Ultrasonography; D053039:Ureterolithiasis / Q000145:classification / Q000150:complications* / Q000000981:diagnostic imaging*