MATURATIONAL CHANGES IN ARTERIAL IMPEDANCE OF THE NORMAL TESTIS IN BOYS - DOPPLER SONOGRAPHIC STUDY

OBJECTIVE. The use of color Doppler sonography to diagnose scrotal dis orders in children has been hampered by the small size of the vessels and the slow blood flow compared with those in adults. Spectral analys is is the best means available of confirming the vascular origin of qu estionable color-flow signals arising from testes of small volume. The range of normal and abnormal Doppler sonographic arterial waveforms a rising from the testis in boys, as distinct from those in adults, has never been described. The purpose of our study was to establish the no rmal range of testicular arterial impedance, measured as resistive ind ex (RI), in both prepubertal and pubertal/post pubertal boys. SUBJECTS AND METHODS. Bilateral scrotal color Doppler sonography was performed in 33 healthy boys aged 3 days to 17.5 years. The mean RI in the pare nchymal artery was measured in 44 testes and plotted against testicula r volume. Chi-square statistics were used to test differences in mean RI, testicular volume, and age between testes with volumes of 4 cm(3) or less and testes with volumes greater than 4 cm(3). RESULTS. In test es with volumes of 4 cm(3) or less, the mean RI ranged from 0.39 to 1. 00 (mean, 0.87), and in testes with volumes greater than 4 cm(3), the RI ranged from 0.43 to 0.75 (mean, 0.57). In 20 of 30 testes with volu mes of 4 cm(3) or less, the RI of parenchymal arteries was equal to 1. 00 (i.e., diastolic flow was undetectable). Mean RI, testicular volume , and age were significantly different between testes with volumes of 4 cm(3) or less and testes with volumes greater than 4 cm(3) (p < .001 for all variables). CONCLUSION. Mean testicular RI in our samples of pubertal and postpubertal boys is decreased compared with the mean RI in prepubertal boys. Diastolic arterial flow may not be detectable in normal testes with volumes of 4 cm(3) or less. Despite the existence o f a statistically significant difference in mean RI between prepuberta l and pubertal/postpubertal testes, substantial variability exists wit hin each group, particularly among the prepubertal testes. Norms of te sticular flow previously established for adults are therefore not rout inely applicable to prepubertal boys with testicular volumes less than 4 cm(3). However, RI values in normal pubertal and postpubertal boys where testicular volumes exceed 4 cm(3) are comparable to those previo usly described in adults.