Quantification of fat deposition in the testis and epididymis using mDIXON Quant sequence: correlation with age and ejaculation.

PURPOSE: The objective of this study was to quantitatively assess fat deposition in the testis and epididymis by measuring the fat/water signal ratios with mDIXON Quant and to investigate its correlation with age and ejaculation.

MATERIALS AND METHODS: Routine pelvic magnetic resonance imaging and mDIXON Quant were performed on 120 subjects. The fat/water signal ratios of the testis and epididymis were measured based on the fat/water signal intensity on mDIXON Quant.

RESULTS: The fat/water signal ratio values of the testis and epididymis in the early adulthood group (0.952-3.550%, p < 0.05, and 5.182-12.725%, p < 0.05, respectively) were significantly higher than those in the late childhood group (0.611-2.198% and 1.310-4.520%) and in the youth group (0.659-2.360% and 1.568-4.469%), and they were lower than those in the middle adulthood group (1.538-4.249%, p < 0.05, and 5.830-19.002%, p < 0.05). The fat deposition decreased in the testis of the youth group, who ejaculated more than ten times per month (0.750-2.022%, p < 0.05), and the fat/water signal ratios of the epididymis decreased in one subject in the early adulthood group who had three ejaculations within 12 h.

CONCLUSION: The findings of this study suggest that mDIXON Quant may be useful as a noninvasive, quantitative, and objective method for evaluating the fat deposition of the testis and epididymis. This method can provide guidance for fat deposition in the testis and epididymis in different age groups with varying ejaculation experiences. Additionally, our findings may facilitate more accurate diagnosis and monitoring of the reproductive function of the testis and epididymis by quantitatively measuring their fat deposition with age.