Ultrahigh b‐values MRI in normal human prostate: Initial research on reproducibility and age‐related differences

Abstract

Purpose To investigate the reproducibility of diffusion‐weighted imaging (DWI) with ultrahigh b‐values, and analyze the age‐related differences in normal prostates. Materials and Methods In all, 67 healthy participants were divided into three age groups (group A, 15–30 years; group B, 31–50 years; group C, ≥51 years), and underwent DWI scanning twice with 15 b‐factors from 0 to 3000 at 3.0T. Triexponential fits were applied to calculate the molecular diffusion coefficient (D), the pseudo‐diffusion coefficient (D*), the ultrahigh apparent diffusion coefficient (ADC uh ), and perfusion fraction (f). The interobserver and short‐term interscan reproducibility were evaluated, and the change in these parameters with age were assessed. Results The D, ADC uh , and f values presented good to excellent reproducibility. With increasing age, a trend of increasing D values was observed, with significant difference in both peripheral zone (PZ, P = 0.01) and central gland (CG, P = 0.01) of normal prostate tissue. The f value increased in the CG beginning at 50 years of age while the ADC uh value decreased in the PZ after 50 years of age; all of them showed significant differences between groups A and C and groups B and C ( P = 0.01/0.01). Conclusion The D, ADC uh , and f values have good to excellent reproducibility in the normal prostate, and these values change with age. The ultrahigh b‐values magnetic resonance imaging (MRI) can provide additional information (ADC uh ), which is different from the IVIM (intravoxel incoherent motion)‐derived parameters. Level of Evidence: 1 Technical Efficacy: Stage 2 J. MAGN. RESON. IMAGING 2017;46:801–812