Amide proton transfer-weighted magnetic resonance imaging for the evaluation of testicular spermatogenic function: a preliminary study.

Purpose: To determine the amide proton transfer-weighted (APTw) imaging features in testes with age, and to assess the feasibility of APTw magnetic resonance imaging (MRI) in assessing testicular spermatogenic function.

Methods: A total of 23 male patients with clinically confirmed hypospermatogenesis caused by epididymo-orchitis were included in the case group (group A) and another 93 men (age range, 20-80 years) were included in the control group. The control group was divided into four subgroups: group B1 (20-34 years, n = 25), group B2 (35-49 years, n = 23), group B3 (50-64 years, n = 21), and group B4 (65-80 years, n = 24). All participants underwent 3.0T MRI scan, and the APT signal intensity (SI) and apparent diffusion coefficient (ADC) value of each testis were examined. The ADC and APT SI were independently measured by two radiologists blinded to clinical data, and average values were calculated. A power analysis was conducted to determine the required sample size.

Results: APT SI was negatively correlated with age (r = -0.510, < 0.001), whereas ADC was positively correlated with age (r = 0.317, = 0.006). The APT SI was significantly higher in group A (1.77 ± 0.41) than in group B1 (1.43 ± 0.21), group B2 (1.37 ± 0.31), group B3 (1.30 ± 0.35), and group B4 (1.20 ± 0.35) (all < 0.01). The ADC was significantly higher in group A [(0.549 ± 0.091) × 10 mm/s] compared with group B1 [(0.449 ± 0.047) × 10 mm/s], group B2 [(0.475 ± 0.022) × 10 mm/s], and group B3 [(0.488 ± 0.051) × 10 mm/s] (all < 0.01), whereas no statistically significant difference was found between group A and group B4 ( > 0.05).

Conclusion: The APT SI of the normal testes decreased with age, whereas a significant elevation of APT SI was detected in patients with hypospermatogenesis caused by epididymo-orchitis.

Clinical Significance: Hypospermatogenesis caused by degeneration or inflammation can be differentiated by APT quantity combined with ADC value.