Relationship between Testicular Volume and Sperm Count in Infertile Men in Southern Nigeria

Background: The gold standard for assessment of testicular function in men being evaluated for infertility is semen analysis. There however is a correlation between the testicular volume and testicular function. Ultrasound of the testicles can be used to measure its volume and thus based on this relationship be a pointer to testicular function.

Aim: To examine the association between testicular volumes obtained by scrotal ultrasound and testicular function in infertile men in Southern Nigeria.

Patients and Methods: A prospective study of 100 infertile men referred to the Department of Radiology in the University of Port-Harcourt Teaching Hospital, over a nine month period for scrotal ultrasound examination. All scrotal ultrasound scans were carried out with a Mindray DC-8 diagnostic ultrasound system using a 7.5MHz transducer. Statistical analysis was carried out using Statistical Package for the Social Sciences (SPSS) 20.0. Pearson's Correlation was used for the correlation studies with a p values of less than 0.05 considered as statistically significant.

Results: The mean testicular volume (MTV) for the study population was 13.14 ± 5.16 cm3.

A statistically significant positive correlation was noted between the total sperm count and testicular volume (r=0.397, p<0.0001). There was a peak in sperm concentration at a mean testicular volume (MTV) of 25.1-27 cm3. Severe oligospermia (sperm concentration <5 million cells/ml) was noted at a MTV of 7 cm3 and less.

Conclusion: Testicular volumes obtained from scrotal ultrasound examination correlate positively with sperm concentration in a non-linear fashion. A mean testicular volume of greater than 7 cm3 is necessary for sperm concentrations of > 5 million cells/ml.