Assessment of testicular function in experimental varicocele rats by phosphorus-31 magnetic resonance spectroscopy

MR Spectra of Normal Adult Testes and Variations with Age: Preliminary Observations

OBJECTIVES

The aim was to determine the proton MR (1H-MR) spectra of normal adult testes and variations with age.

METHODS

Forty-one MR spectra of normal testes, including 16 testes from men aged 20-39 years (group I) and 25 testes from men aged 40-69 years (group II), were analyzed. A single-voxel point-resolved spectroscopy sequence (PRESS), with TR/TE: 2000/25 ms was used. The volume of interest was placed to include the majority of normal testicular parenchyma. Association between normalized metabolite concentrations, defined as ratios of the calculated metabolite concentrations relative to creatine concentration, and age was assessed.

RESULTS

Quantified metabolites of the spectra were choline (Cho), creatine (Cr), myo-inositol (mI), scyllo-inositol, taurine, lactate, GLx compound, glucose, lipids, and macromolecules resonating at 0.9 ppm (LM09), around 20 ppm (LM20), and at 13 ppm (LM13). Most prominent peaks were Cho, Cr, mI, and lipids. A weak negative correlation between mI and age (P = 0.015) was observed. Higher normalized concentrations of Cho (P = 0.03), mI (P = 0.08), and LM13 (P = 0.05) were found in group I than in group II.

CONCLUSIONS

1H-MR spectra of a normal adult testis showed several metabolite peaks. A decrease of levels of Cho, mI, and LM13 was observed with advancing age.

KEY POINTS

• Single-voxel PRESS MRS of a normal testis is feasible. • 1H-MR spectra of a normal testis showed several metabolite peaks. • Most prominent peaks were Cho, Cr, mI, and lipids. • A decrease of Cho, mI, and LM13 was seen with advancing age.

MR imaging of scrotum

Magnetic resonance (MR) imaging of the scrotum has been used as a valuable supplemental diagnostic modality in evaluating scrotal pathology, mostly recommended in cases of inconclusive sonographic findings. Because of the advantages of the technique, MR imaging of the scrotum may provide valuable information in the detection and characterization of various scrotal diseases. The technique may accurately differentiate intratesticular from extratesticular mass lesions and provide important information in the preoperative characterization of the histologic nature of scrotal masses. An accurate estimation of the local extent of testicular carcinomas in patients for whom testis-sparing surgery is planned is possible.

Do experimentally induced ipsilateral testicular torsion, vas deferens obstruction, intra-abdominal testis or venous obstruction damage the contralateral testis through a common mechanism?

OBJECTIVE

To evaluate if various conditions affecting the ipsilateral testis which also damage the contralateral testis share a common pathway for their effects.

MATERIALS AND METHODS

The study comprised five groups of 10 adult rats which underwent surgery to produce (on their left sides); group 1, a sham operation (control); group 2, testicular torsion; group 3, vas deferens obstruction; group 4, an intra-abdominal testis; and group 5, venous obstruction. The ipsilateral and contralateral testes were harvested 4 weeks after surgery. The relative proportions of haploid cells, the mean seminiferous tubular diameter (MSTD), mean testicular biopsy scores (MTBS), and lactate and hypoxanthine levels were determined and compared.

RESULTS

The proportions of haploid cells in the ipsilateral and the contralateral testes of groups 2-5 were significantly lower than those of the corresponding testes of the control group. The MSTD and MTBS of the ipsilateral testes in groups 2-5 were also significantly lower than the ipsilateral testes of controls and the contralateral testes within the same groups. While the MSTD and MTBS of the contralateral testes of groups 1 and 5 were not significantly different, those of the contralateral testes of groups 2-4 were significantly less than that of group 1. The lactic acid and hypoxanthine levels of the ipsilateral and contralateral testes were significantly increased in groups 2 and 3. While only the hypoxanthine level of group 5 increased significantly, both variables were not significantly different between the ipsilateral testes of groups 1 and 4.

CONCLUSIONS

These four treatments damaged both the ipsilateral and contralateral testes. As the lactic acid and hypoxanthine levels within the contralateral testis were greater than in the controls, testicular torsion and vas deferens obstruction seem to share a common pathway (which may be a reflex decrease in contralateral testicular blood flow) for their effects on the contralateral testis.