title: CT Urography for Diagnosis of Upper Urinary Tract Urothelial Carcinoma: Are Both Nephrographic and Excretory Phases Necessary?
abstract: OBJECTIVE
  The objective of our study was to compare the diagnostic performance of nephrographic phase only, excretory phase only, and both nephrographic and excretory phases of CT urography (CTU) for the detection of upper tract urothelial carcinoma.
  
  
  METHODS
  Forty-nine consecutive patients with pathologically proven upper tract urothelial carcinoma who underwent a single-bolus CTU examination were evaluated. Forty-nine control patients with normal findings on two CTU examinations performed at a 1-year interval were included. Two radiologists independently reviewed the 98 CTU examinations at three different sessions (nephrographic phase only, excretory phase only, and both nephrographic and excretory phases simultaneously) and rated the likelihood of the presence of a urothelial carcinoma in each segment of the renal collecting system and ureter using a 5-point scale. Sensitivity, specificity, and AUC of ROC curve were calculated per segment and per patient.
  
  
  RESULTS
  A total of 314 segments, 56 of which contained tumors, were evaluated. In the per-segment analysis for reviewers 1 and 2, the sensitivity, specificity, and AUC, respectively, were as follows: 88%, 98%, and 0.95 and 84%, 97%, and 0.94 for the nephrographic phase; 79%, 98%, and 0.91 and 89%, 98%, and 0.95 for the excretory phase; and 88%, 99%, and 0.95 and 89%, 99%, and 0.96 for the combined nephrographic and excretory phases. The AUC of the combined nephrographic and excretory phases was significantly higher than that of the nephrographic phase (per-patient analysis, reviewer 2) and that of excretory phase (per-segment analysis, reviewer 1) but was not significantly different in any other comparisons.
  
  
  CONCLUSIONS
  The nephrographic and excretory phases are complementary for the detection of upper tract urothelial carcinoma.
authors: 1 Department of Radiology, Mayo Clinic, 200 First St, SW, Rochester, MN 55905.|2 Present address: Department of Radiology, Nagoya City University Graduate School of Medical Sciences, Nagoya, Japan.
authors: Mitsuru
authors: M
authors: Takeuchi
authors: 1 Department of Radiology, Mayo Clinic, 200 First St, SW, Rochester, MN 55905.
authors: Aaron J
authors: AJ
authors: Konrad
authors: 1 Department of Radiology, Mayo Clinic, 200 First St, SW, Rochester, MN 55905.
authors: Akira
authors: A
authors: Kawashima
authors: 3 Department of Urology, Mayo Clinic, Rochester, MN.
authors: Stephen A
authors: SA
authors: Boorjian
authors: 1 Department of Radiology, Mayo Clinic, 200 First St, SW, Rochester, MN 55905.
authors: Naoki
authors: N
authors: Takahashi
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D002277:Carcinoma / Q000000981:diagnostic imaging*; D003287:Contrast Media / Q000008:administration & dosage; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D061330:Multidetector Computed Tomography / Q000379:methods*; D011237:Predictive Value of Tests; D012372:ROC Curve; D012189:Retrospective Studies; D014567:Urography / Q000379:methods*; D014571:Urologic Neoplasms / Q000000981:diagnostic imaging*; D019459:Urothelium
chemical_list: D003287:Contrast Media
keywords: CT urography; diagnostic performance; excretory phase; nephrographic phase; upper urinary tract urothelial carcinoma