Diffusion-weighted magnetic resonance imaging of urinary epithelial cancer with upper urinary tract obstruction: preliminary results.

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=800 s/mm(2)). 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 x 10(-3) mm(2)/s, which was significantly lower than that of the lumens of the ureter or renal pelvis (3.32+/-0.44 x 10(-3) mm(2)/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.