Potential of MRI and 31P MRS in the evaluation of experimental testicular trauma.

Objectives: To prognosticate and assess the metabolic status of germ cells of the testis after unilateral blunt testicular trauma using both magnetic resonance imaging (MRI) and magnetic resonance spectroscopy (MRS). MRI is a noninvasive technique suitable for evaluating testicular trauma, and MRS is useful in assessing the metabolic status of the testis.

Methods: The right testis of 35 male prepubertal Wistar rats, aged 30 days, was explored through an inguinal incision. The rats were randomized into control (group 1, sham surgery, n = 10) and study (n = 25) groups. The study group received unilateral blunt testicular trauma to the right testis. T(1)- and T(2)-weighted proton MRI of the ipsilateral testis were taken 6 hours after sham surgery or injury, and the rats were stratified on the basis of the absence or presence of intratesticular hemorrhage on MRI into groups 2 (n = 14) and 3 (n = 11), respectively. At 60 days of age, the contralateral testis of each rat was evaluated by 31P MRS and histologic examination. Quantification of phosphomonoesters, phosphodiesters, phosphocreatine, and adenosine triphosphate (gamma, alpha, and beta) was done.

Results: A statistically significant difference (P <0.05) in the phosphomonoester/adenosine triphosphate ratio, seminiferous tubular diameter, and Johnsen score of the contralateral testis was observed, indicating decreased testicular maturation of the contralateral testis in group 3 rats compared with groups 1 and 2.

Conclusions: MRI after testicular trauma helped to stratify the extent of injury as determined by the presence or absence of intratesticular hemorrhage with prognostic value; 31P MRS and histologic examination revealed that testicular trauma significantly affects the maturation of the contralateral testis.