Age‐related and zonal anatomical changes of apparent diffusion coefficient values in normal human prostatic tissues

Abstract

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 Ϯ 0.27 ϫ10 -3 mm 2 /second for PZ and 1.26 Ϯ 0.12 ϫ10 -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 ϭ 0.526, P Ͻ 0.0001; r ϭ 0.190, P ϭ 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.

Apparent diffusion coefficient values in peripheral and transition zones of the prostate: Comparison between normal and malignant prostatic tissues and correlation with histologic grade

“…These differences may be attributed to factors such as the subject's age, size of the static magnetic field from the MR scanner used (1.5 or 3.0 T), b-factor settings, and use of parallel imaging. As in previous reports (12,13,16,18,20,21,30), these findings show that ADC values were higher in normal PZ than in normal CG. In addition, another recent report demonstrated that ADC values increased with age in both PZ and CG (30).…”

“…As in previous reports (12,13,16,18,20,21,30), these findings show that ADC values were higher in normal PZ than in normal CG. In addition, another recent report demonstrated that ADC values increased with age in both PZ and CG (30). ADC values observed in normal regions in the present study are compatible with those results.…”

“…Thus, although the subjects with lower urinary tract symptoms have been excluded in this study, a fair percentage of normal cases can be considered in some way to have asymptomatic hyperplastic changes in the prostate. Tamada et al (30) reported that ADC values within the CG increase with age, reflecting the histologic changes such as hyperplasia. Therefore, the efficiency of ADC values to diagnose prostate cancer may decrease in younger age groups, especially in the CG.…”

Diffusion weighted MRI for detecting and monitoring cancer: a review of current applications in body imaging

“…However, higher field strengths can also introduce more challenges regarding susceptibility effects. The use of higher b values (0 to 1 000 and 2 000 s/mm 2 ) can improve lesion detection at the expense of a lower signal-to-noise ratio (82)(83)(84)(85). Prostate cancer lesions demonstrate hyperintense signal characteristics compared with the healthy peripheral zone on raw DWI, whereas they show a decreased signal intensity relative to healthy peripheral zone on ADC maps (86).…”

“…DWI has a low signal noise ratio (SNR), but the emergence of high-field-strength magnets, the widespread use of endorectal coils and parallel imaging approaches will yield better SNR and, therefore, better spatial/temporal resolution for DWI. Additionally, the use of higher gradient strengths (e.g., b values of 1 000 to 2 000 s/mm 2 ) improves the performance of DWI for lesion detection (83)(84)(85)97). Moreover, DWI currently stands as the most promising quantitative MRI technique for improving our understanding of the nature of prostate cancer lesions (Fig.…”