Evaluation of diffusion weighted imaging in differentiating prostate cancer and benign hyperplasia

Objective: To describe diffusion weighted imaging (DWI) and apparent diffusion coefficient (ADC) map appearance of benign hyperplasia (BPH) and prostate cancer(PCa), and to evaluate DWI and ADC map and ADC values in differential diagnosis of PCa. Methods: DWI and ADC map findings were reviewed in 18 BPH cases and 25 PCa cases. ADC values of PCa and ADC values of peripheral zone (PZ) and central glands (CG) voxels in BPH were retrospectively measured. Results: On DWI, PZ of BPH demonstrated homogenous slightly signal intensity (SI), CG appeared heterogeneous SI. Twenty-two PCa showed markedly high-signal on DWI and obviously low-signal on ADC map, which both could clearly demonstrate the area of PCa. The invaded seminal vesicles and bone metastases of pelvis also appear similar SI as PCa on DWI and ADC map. ADC values of PCa were significantly lower than PZ(t=-52.46, P< 0.001) and CG(t=-31.49, P<0.001) in BPH. No overlap existed between ADC values of PCa[(0.49± 0.09) x 10-3 mm2/s] and PZ in BPH [(1.27±0.14) x 10-3 mm2/s], only minimal overlap (1/127, 0.7%) existed between ADC values of PCa and CG in BPH[(0.96±0.14) x 10-3 mm2/s]. Conclusion: Both DWI and ADC map can well display PCa location and area, which also can show the involvement of seminal vesicles and bone metastases. BPH and PCa can be differentiated by Both DWI and ADC map and ADC values. (authors)