title: Initial experience of functional imaging of upper urinary tract neoplasm by diffusion-weighted magnetic resonance imaging.
abstract: OBJECTIVE
  Diffusion-weighted (DW) magnetic resonance imaging (MRI) provides functional information widely used in the diagnosis of acute cerebral stroke. We reported our initial experience of this imaging technique of upper urinary tract (UUT) urothelial carcinoma (UC).
  
  
  METHODS
  Diffusion-weighted magnetic resonance imaging was carried out in 10 consecutive patients with suspected UUT UC. With conventional imaging, seven were diagnosed as having renal pelvic tumors and two were highly suspected of having UUT UC. These nine patients were diagnosed histopathologically as having renal pelvic UC by subsequent operation. The last patient was confirmed as experiencing benign stenosis. DW MRI was obtained with a 1.5-T MR imager without a breath-holding sequence. The apparent diffusion coefficient (ADC) values of renal parenchyma, dilated collecting system, and tumor were calculated. The differences were analyzed using Wilcoxon t-test.
  
  
  RESULTS
  On DW MRI, all nine tumors showed hyperintensity with negligible urinary intensity. Two cases of highly suspected UUT UC with unclear conventional MRI had high signal intensity and contrast. The case of benign stenosis had negative DW MRI. The median (range) ADC value of the tumor (0.803 [0.412-0.958] x 10(-3) mm(2)/s) was significantly lower than those of the dilated collecting system (2.19 [1.42-2.40] x 10(-3)) and renal parenchyma (1.28 [0.922-1.45] x 10(-3), respectively (P < 0.01 and P < 0.01).
  
  
  CONCLUSIONS
  This is the first report on the application of DW MRI for a series of UUT UC. With this technique, a clear demonstration of UUT UC could be obtained. Moreover, this imaging technique is potentially useful to identify small lesions if they have a low diffusion coefficient.
authors.affiliation: Department of Urology, Graduate School, Tokyo Medical and Dental University, Tokyo, Japan.
authors.forename: Soichiro
authors.initials: S
authors.lastname: Yoshida
authors.forename: Hitoshi
authors.initials: H
authors.lastname: Masuda
authors.forename: Chikako
authors.initials: C
authors.lastname: Ishii
authors.forename: Kazutaka
authors.initials: K
authors.lastname: Saito
authors.forename: Satoru
authors.initials: S
authors.lastname: Kawakami
authors.forename: Kazunori
authors.initials: K
authors.lastname: Kihara
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D002277:Carcinoma / Q000175:diagnosis*; D038524:Diffusion Magnetic Resonance Imaging; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D014571:Urologic Neoplasms / Q000175:diagnosis*