Age-related and Zonal Anatomical Changes of Apparent Diffusion Coefficient Values in Normal Human Prostatic Tissues

Purpose: To identify age-related changes and differences in the diffusion of water molecules within the prostate, through diffusion-weighted imaging (DWI) of the prostate gland in healthy adult Japanese men.

Materials And Methods: A total of 114 healthy male volunteers (mean age, 55 years; range, 24-81 years) underwent DWI of the prostate with a single-shot echo-planar imaging (EPI) sequence using b-factors of 0 and 1000 seconds/mm(2). Apparent diffusion coefficient (ADC) values of six locations in the peripheral zone (PZ) and two locations in the central gland (CG) were measured and correlations between region and age were examined.

Results: ADC values measured within both PZ and CG regions of the prostate showed a uniform distribution, and no significant differences were found between evaluated regions. However, mean ADC values were 1.64 +/- 0.27 x 10(-3) mm(2)/second for PZ and 1.26 +/- 0.12 x 10(-3) mm(2)/second for CG, representing a significant difference. In addition, significant positive correlations were identified between ADC values for both PZ and CG regions and subject age (r = 0.526, P < 0.0001; r = 0.190, P = 0.0431, respectively).

Conclusion: ADC values within both PZ and CG regions of the prostate increase with age, and this must be taken into consideration when using DWI in the diagnosis of prostate cancer.