title: MR urography in evaluation of acute flank pain: T2-weighted sequences and gadolinium-enhanced three-dimensional FLASH compared with urography. Fast low-angle shot.
abstract: OBJECTIVE
  The aim of this study was to compare the usefulness of breath-hold heavily T2-weighted sequences with gadolinium-enhanced three-dimensional fast low-angle shot (3D FLASH) MR urography in the evaluation of patients with acute flank pain.
  
  
  METHODS
  Forty consecutive patients with symptoms of acute flank pain underwent MR urography followed immediately by excretory urography. Heavily T2-weighted (combined thin-slice half-Fourier acquisition single-shot turbo spin-echo [HASTE] and thick-slab single-shot turbo spin-echo) and 3D FLASH sequences were evaluated separately and independently by two experienced radiologists for the presence, cause, level, and degree of obstruction. Interobserver agreement was calculated using the kappa statistic. Excretory urography and the final clinical diagnosis were used as reference.
  
  
  RESULTS
  Twenty-six patients were found to have unilateral obstruction caused by ureteral stones. Both MR urography methods were excellent for detecting obstruction. In the detection of stones 3D FLASH was superior, with a sensitivity of 96.2% and 100% and specificity of 100% and 100% for observers A and B, respectively, compared with a sensitivity of 57.7% and 53.8% and a specificity of 100% and 100%, respectively, for T2-weighted sequences. The best degree of obstruction was seen with 3D FLASH, and the interobserver agreement was excellent for stone detection (kappa = 0.97).
  
  
  CONCLUSIONS
  T2-weighted sequences alone are not sufficient for examining patients with acute flank pain. However, the combined use of both T2-weighted and 3D FLASH sequences will ensure better confidence in the evaluation of acute suspected renal colic. MR urography can replace conventional excretory urography when the latter is contraindicated or undesirable.
authors.affiliation: Department of Clinical Radiology, Kuopio University Hospital, P.O. Box 1777, FIN-70211 Kuopio, Finland.
authors.forename: M
authors.initials: M
authors.lastname: Sudah
authors.forename: R
authors.initials: R
authors.lastname: Vanninen
authors.forename: K
authors.initials: K
authors.lastname: Partanen
authors.forename: A
authors.initials: A
authors.lastname: Heino
authors.forename: P
authors.initials: P
authors.lastname: Vainio
authors.forename: M
authors.initials: M
authors.lastname: Ala-Opas
mesh_terms: D000208:Acute Disease; D000328:Adult; D000368:Aged; D003287:Contrast Media; D005260:Female; D021501:Flank Pain / Q000209:etiology*; D019786:Gadolinium DTPA; D006801:Humans; D007472:Iohexol; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D015588:Observer Variation; D011446:Prospective Studies; D012680:Sensitivity and Specificity; D014514:Ureteral Calculi / Q000150:complications / Q000175:diagnosis / Q000000981:diagnostic imaging; D014517:Ureteral Obstruction / Q000150:complications / Q000175:diagnosis* / Q000000981:diagnostic imaging; D014551:Urinary Tract / Q000473:pathology*; D014567:Urography
chemical_list: D003287:Contrast Media; D007472:Iohexol; D019786:Gadolinium DTPA