Background: Aside from converted data from orchidometer measurements, there are no referential values for testicular volume ultrasound measurements in children available. Therefore, the aim of this study was to obtain ultrasonographically measured normative data for testicular volumes in 0- to 6-year-old boys.
Methods: A total of 344 boys from different ethnic backgrounds were studied. For the ultrasound measurements, an Aloka SSD-900 was used with a 7.5 mHz linear transducer. Testicular volume was calculated using the formula: length x width x height x (pi/6).
Results: No differences were found either between the various ethnic groups or between the left and right testicle. Mean testicular volume was compared between the different age categories. Mean testicular volume increases significantly in the first 5 months from 0.27 to 0.44 cm(3) after which the volume decreases to 0.31 cm(3) at approximately 9 months. During the following years, testicular volume remains stable.
Conclusions: This study provides normal values for ultrasonographically measured testicular volumes in 0- to 6-year-old boys. Ultrasound is a valid method to measure small pre-pubertal testicles as it is able to detect minor changes in volume in relation to established physiological changes in the first year of life.