title: Relationship between duration of pain and secondary signs of obstruction of the urinary tract on unenhanced helical CT.
abstract: OBJECTIVE
  The objective of this study was to investigate the relationship between duration of flank pain and the frequency of secondary signs of ureteral obstruction on unenhanced helical CT.
  
  
  METHODS
  The duration of flank pain was prospectively determined in 227 consecutive patients diagnosed with acute ureterolithiasis on unenhanced helical CT. These CT studies were evaluated for the presence or absence of perinephric stranding, ureteral dilatation, perinephric fluid, collecting system dilatation, periureteral stranding, and nephromegaly. The frequency of each sign was determined as a function of the duration of pain.
  
  
  RESULTS
  The frequency of moderate or severe perinephric stranding increased from 5% at 1--2 hr to 51% at 7--8 hr (p < 0.001); ureteral dilatation increased from 84% at 1--2 hr to 97% at more than 8 hr (p < 0.03); moderate or severe perinephric fluid increased from 0% at 1--2 hr to 22% at 3--4 hr (p < 0.03); collecting system dilatation increased from 68% at 1--2 hr to 89% at 7-8 hr (p < 0.03); periureteral stranding increased from 35% at 1--2 hr to 76% at 7--8 hr (p < 0.004); and nephromegaly increased from 40% at 1--2 hr to 54% at 7--8 hr (p < 0.36).
  
  
  CONCLUSIONS
  All CT secondary signs of ureteral obstruction except nephromegaly showed a significant increase in frequency as duration of flank pain increased. This observation may explain why the CT studies of some patients with acute ureterolithiasis show negative findings for some or all CT secondary signs of obstruction. Therefore, knowledge of the duration of pain is important when interpreting unenhanced CT studies in patients with acute ureterolithiasis.
authors.affiliation: Department of Diagnostic Radiology, Yale University School of Medicine, 333 Cedar St., New Haven, CT 06510, USA.
authors.forename: M J
authors.initials: MJ
authors.lastname: Varanelli
authors.forename: D M
authors.initials: DM
authors.lastname: Coll
authors.forename: J A
authors.initials: JA
authors.lastname: Levine
authors.forename: A T
authors.initials: AT
authors.lastname: Rosenfield
authors.forename: R C
authors.initials: RC
authors.lastname: Smith
mesh_terms: D000328:Adult; D005260:Female; D006801:Humans; D008297:Male; D010146:Pain / Q000209:etiology* / Q000503:physiopathology; D011446:Prospective Studies; D013997:Time Factors; D014057:Tomography, X-Ray Computed / Q000379:methods*; D014514:Ureteral Calculi / Q000150:complications / Q000000981:diagnostic imaging*; D014517:Ureteral Obstruction / Q000150:complications / Q000000981:diagnostic imaging*