Diffusion-weighted imaging of the prostate at 3 T for differentiation of malignant and benign tissue in transition and peripheral zones: Preliminary results

Objective: To evaluate prospectively the use of apparent diffusion coefficients (ADCs) for the differentiation of malignant and benign tissue in the transition (TZ) and peripheral (PZ) zones of the prostate diffusion-weighted imaging (DWI) at 3 T magnetic resonance imaging (MRI) using a phased-array coil. Methods: The DWI at 3-T MRI was performed on a total of 35 patients before radical prostatectomy. A single-shot echo-planar imaging DWI technique with b = 0 and b = 1000 s/mm(2) was used. The ADC values were measured in both benign and malignant tissues in the PZ and TZ using regions of interest. Differences between PZ and TZ ADC values were estimated using a paired Student t test. Presumed ADC cutoff values in the PZ and TZ for the diagnosis of cancer were assessed by receiver operating characteristic analysis. Results: The ADC values of malignant tissues were significantly lower than those of benign tissues in the PZ and TZ (P < 0.001; 1.32 + 0.24 x 10(-3) mm(2)/s vs 1.97 +/- 0.25 x 10(-3) mm(2)/S, and 1.37 +/- 0.29 x 10(-3) mm(2)/s vs 1.79 +/- 0.19 x 10(-3) mm(2) /s, respectively). For tumor diagnosis, Cutoff values of 1.67 x 10(-3) mm(2)/S (PZ) and 1.61 x 10(-3) mm(2)/S (TZ) resulted in sensitivities and specificities of 94% and 91% and 90% and 84%, respectively. Conclusions: The DWI of the prostate at 3T MRI using a phasedarray coil was useful for the differentiation of malignant and benign tissues in the TZ and PZ.