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

Abstract

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. T₁- and T₂-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.