title: Delineation of upper urinary tract segments at MDCT urography in patients with extra-urinary mass lesions: retrospective comparison of standard and low-dose protocols for the excretory phase of imaging.
abstract: OBJECTIVE
  Excretory-phase CT urography (CTU) may replace excretory urography in patients without urinary tumors. However, radiation exposure is a concern. We retrospectively compared upper urinary tract (UUT) delineation in low-dose and standard CTU.
  
  
  METHODS
  CTU (1-2 phases, 120 KV, 4 × 2.5 mm, pitch 0.875, i.v. non-ionic contrast media, iodine 36 g) was obtained with standard (14 patients, n = 27 UUTs, average 175.6 mAs/slice, average delay 16.8 min) or low-dose (26 patients, n = 86 UUTs, 29 mAs/slice, average delay 19.6 min) protocols. UUT was segmented into intrarenal collecting system (IRCS), upper, middle, and lower ureter (UU,MU,LU). Two independent readers (R1,R2) graded UUT segments as 1-not delineated, 2-partially delineated, 3-completely delineated (noisy margins), 4-completely delineated (clear margins). Chi-square statistics were calculated for partial versus complete delineation and complete delineation (clear margins), respectively.
  
  
  RESULTS
  Complete delineation of UUT was similar in standard and low-dose CTU (R1, p > 0.15; R2, p > 0.2). IRCS, UU, and MU clearly delineated similarly often in standard and low-dose CTU (R1, p > 0.25; R2, p > 0.1). LU clearly delineated more often in standard protocols (R1, 18/6 standard, 38/31 low-dose, p > 0.1; R2 18/6 standard, 21/48 low-dose, p < 0.05).
  
  
  CONCLUSIONS
  Low-dose CTU sufficiently delineated course of UUT and may locate obstruction/dilation, but appears unlikely to find intraluminal LU lesions.
authors.affiliation: Department of Urology, University of Munich, Munich, Germany. Ulrike.Mueller-Lisse@med.uni-muenchen.de
authors.forename: Ulrike L
authors.initials: UL
authors.lastname: Mueller-Lisse
authors.forename: Eva M
authors.initials: EM
authors.lastname: Coppenrath
authors.forename: Thomas
authors.initials: T
authors.lastname: Meindl
authors.forename: Christoph
authors.initials: C
authors.lastname: Degenhart
authors.forename: Michael K
authors.initials: MK
authors.lastname: Scherr
authors.forename: Christian G
authors.initials: CG
authors.lastname: Stief
authors.forename: Maximilian F
authors.initials: MF
authors.lastname: Reiser
authors.forename: Ullrich G
authors.initials: UG
authors.lastname: Mueller-Lisse
mesh_terms: D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009369:Neoplasms / Q000000981:diagnostic imaging*; D017410:Practice Guidelines as Topic; D011829:Radiation Dosage; D011835:Radiation Protection / Q000592:standards*; D014057:Tomography, X-Ray Computed / Q000379:methods* / Q000592:standards*; D014554:Urination; D014567:Urography / Q000379:methods*
references.citation: Eur Radiol. 2006 Aug;16(8):1667-74
references.pmid: 16583216
references.citation: Eur Radiol. 2006 Dec;16(12):2670-86
references.pmid: 16953373
references.citation: J Comput Assist Tomogr. 2006 Sep-Oct;30(5):751-7
references.pmid: 16954923
references.citation: Eur Radiol. 2008 Jan;18(1):4-17
references.pmid: 17973110
references.citation: Radiology. 2005 Apr;235(1):116-23
references.pmid: 15716388
references.citation: J Comput Assist Tomogr. 2009 Jan-Feb;33(1):96-100
references.pmid: 19188794
references.citation: Eur Radiol. 2007 Sep;17(9):2318-24
references.pmid: 17429649
references.citation: J Comput Assist Tomogr. 2001 May-Jun;25(3):343-7
references.pmid: 11351181
references.citation: AJR Am J Roentgenol. 2002 May;178(5):1058-62
references.pmid: 11959701
references.citation: Eur Radiol. 2007 Oct;17(10):2512-8
references.pmid: 17429641
references.citation: Acta Radiol. 2009 May;50(4):446-54
references.pmid: 19308762
references.citation: Abdom Imaging. 2008 Nov-Dec;33(6):707-16
references.pmid: 18253780
references.citation: Rofo. 2001 Mar;173(3):176-80
references.pmid: 11293855
references.citation: Clin Imaging. 2009 Sep-Oct;33(5):369-73
references.pmid: 19712817
references.citation: Acad Radiol. 2001 Nov;8(11):1100-6
references.pmid: 11721809
references.citation: Eur Radiol. 2006 Sep;16(9):1982-9
references.pmid: 16568267
references.citation: Radiology. 2002 Dec;225(3):783-90
references.pmid: 12461262
references.citation: AJR Am J Roentgenol. 1998 May;170(5):1261-7
references.pmid: 9574598
references.citation: AJR Am J Roentgenol. 2003 Feb;180(2):305-11
references.pmid: 12540420