Background: Various malignant tumors of the body show high signal intensity on diffusion-weighted magnetic resonance imaging (DWI). In the genitourinary region, DWI is expected to have a role in detecting urinary epithelial cancer noninvasively.
Purpose: To demonstrate the feasibility of DWI for the diagnosis of urinary epithelial cancer with upper urinary tract obstruction.
Material and Methods: Twenty upper urinary tract cancers in 16 patients were evaluated by high-b-value DWI (b=800s/mm2). The signal intensity was visually evaluated, and the apparent diffusion coefficients (ADCs) were measured.
Results: All urinary epithelial cancers showed high signal intensity on DWI. The ADC in cancerous lesions was 1.31±0.27×10−3 mm2/s, which was significantly lower than that of the lumens of the ureter or renal pelvis (3.32±0.44×10−3 mm2/s; P<0.001). Maximum intensity projection images of DWI in combination with static-fluid MR urography provided three-dimensional entire urinary tract imaging with the extension of tumors.
Conclusion: DWI is useful in the tumor detection and in evaluating the tumor extension of urinary epithelial cancer in patients with upper urinary tract obstruction.
