Evaluation of testicular volume in males with congenital hypogonadotropic hypogonadism: a comparative analysis

Estimating accurate testicular volume (TV) of congenital hypogonadotropic hypogonadism (CHH) individuals is challenging due to the typically small testicular size. Ultrasound (USG) emerges as a vital solution, enabling precise measurements and reproducible results. The purpose of the study was to assess the three-dimensional measurement of the testis using USG and its volume was estimated using Ellipsoid (E) and Lambert (L) formulae and compared these with the TV by Prader orchidometer (OrTV).

This is an exploratory analysis of data taken from a clinical trial conducted from May 2022 to March 2024 which included 94 testes from 47 CHH participants. The OrTVs and USGTVs were assessed at baseline and every three months till the completion of the study making a total of 348 observations. The three-dimensional measurement of the testes was noted and TVs were calculated using the above formulae.

The mean age of the participants was 25.8 ± 6.14 years with a mean height of 169.9 ± 8.42 cm and body mass index (BMI) of 22.4 ± 4.72 kg/m². The baseline mean OrTV, USGTV(E) and USGTV(L) were 2.15 ± 0.79 ml, 0.69 ± 0.43 ml and 0.93 ± 0.59 ml respectively. The smallest OrTV observed was 1 ml with its respective mean USGTV of 0.41 ± 0.2 ml(E) and 0.56 ± 0.27 ml(L). An OrTV of 4 ml had a mean USGTV of 1.11 ± 0.42 ml(E) and 1.51 ± 9.57 ml(L). At spermatogenesis, the mean OrTV was 8.84 ± 3.13 ml with the USGTV determined to be 4 ± 1.46 ml(E) and 5.46 ± 1.99 ml(L).

The study revealed that all CHH patients at diagnosis had OrTV < 4 ml. This corresponds to a USG TV cut-off of 1.11 ml using the Ellipsoid formula and 1.51 ml with the Lambert formula, which could serve as a USG diagnostic criterion for CHH.