RESUMO
PURPOSE: We compared magnetic resonance imaging (MRI) with radical prostatectomy specimens to evaluate the diagnostic performance of diffusion-weighted imaging (DWI) and the apparent diffusion coefficient (ADC) value for prostate cancer localization. MATERIALS AND METHODS: We performed a retrospective study of 44 patients who underwent radical prostatectomy. We compared MRI with pathological specimens (74 tumors) to evaluate their diagnostic performance of cancer localization. The ADC value was measured in cancerous and non-cancerous prostate tissues. RESULTS: Of 74 tumors, digital rectal examination, transrectal ultrasonography, T2-weighted imaging (T2WI), DWI, T2WI and DWI detected 9 (12.2%), 9 (12.2%), 26 (35.1%), 30 (40.5%), and 48 (64.9%) tumors, respectively. The mean ADC value was lower in cancerous tissues than in non-cancerous tissues (0.86 +/- 0.15 versus 1.24 +/- 0.16 x 10(-3) mm2/s). The mean ADC values of cancerous and non-cancerous tissues were: 0.85 +/- 0.15 versus 1.28 +/- 0.17 x 10(-3) mm2/s in the peripheral zone; and 0.87 +/- 0.15 versus 1.19 +/- 0.14 x 10(-3) mm2/s in the transition zone. The mean ADC value in patients with a Gleason score of 8 or 9 (0.76 +/- 0.12 x 10(-3) mm2/s) was lower than that in patients with a Gleason score of 6 or 7 (0.86 +/- 0.15 x 10(-3) mm2/s). CONCLUSION: DWI and ADC value were considered to be useful for the diagnosis of prostate cancer localization.
