title: Imaging characteristics of papillary renal cell carcinoma by computed tomography scan and magnetic resonance imaging.
abstract: OBJECTIVE
  To analyse the differences in the patterns between clear and papillary renal cell carcinomas using magnetic resonance imaging (MRI) and dual-phase helical computed tomography (CT).
  
  
  METHODS
  We examined seven patients with papillary renal cell carcinoma, and six with clear cell carcinoma. The highest attenuation value of tumors in the corticomedullary phase (CMP) and the excretory phase (EP) was measured using the observer-defined region of interest (ROI). MRI consisted of T1-weighted and T2-weighted spin-echo imaging.
  
  
  RESULTS
  All five tumors except for one with papillary renal cell carcinoma showed homogenous hypointensity, but all six tumors with clear cell carcinoma showed heterogeneous hyperintensity on their T2-weighted images. In the CMP, the mean CT numbers of the papillary renal cell carcinomas were significantly lower than those of the clear cell carcinomas. The mean enhancement of the papillary renal cell carcinomas in the CMP and the EP was significantly lower than that of the clear renal cell carcinomas. The mean CT numbers of the clear cell carcinomas in the CMP were markedly increased from those on the unenhanced CT; those in the EP were decreased gradually. But the mean CT numbers of the papillary renal cell carcinomas in the EP were still slightly more increased than those in the CMP. The enhancement patterns of the papillary renal cell carcinomas in the CMP and the EP were homogenous, but those of the clear cell carcinomas were heterogeneous.
  
  
  CONCLUSIONS
  We can speculate the differential diagnosis from clear to papillary renal cell carcinoma using MRI and dual-phase helical CT.
authors.affiliation: Deartment of Radiology, Osaka Medical Center for Cancer and Cardiovascular Diseases, Osaka, Japan.
authors.forename: Kyo
authors.initials: K
authors.lastname: Tsuda
authors.forename: Toshiaki
authors.initials: T
authors.lastname: Kinouchi
authors.forename: Go
authors.initials: G
authors.lastname: Tanikawa
authors.forename: Yumiko
authors.initials: Y
authors.lastname: Yasuhara
authors.forename: Masahiro
authors.initials: M
authors.lastname: Yanagawa
authors.forename: Kenichi
authors.initials: K
authors.lastname: Kakimoto
authors.forename: Yutaka
authors.initials: Y
authors.lastname: Ono
authors.forename: Norio
authors.initials: N
authors.lastname: Meguro
authors.forename: Osamu
authors.initials: O
authors.lastname: Maeda
authors.forename: Jun
authors.initials: J
authors.lastname: Arisawa
authors.forename: Michiyuki
authors.initials: M
authors.lastname: Usami
mesh_terms: D000328:Adult; D000368:Aged; D002292:Carcinoma, Renal Cell / Q000175:diagnosis*; D005260:Female; D006801:Humans; D007680:Kidney Neoplasms / Q000175:diagnosis*; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D014057:Tomography, X-Ray Computed