a-
b-Spectra from intratesticular arteries in children. (a) Waveform obtained in a 12-year-old boy shows a normal low-resistance flow pattern. (b) Waveform obtained in a 2-month-old boy with a testicular volume of 0.7 cm3 shows higher resistance than in a, a finding considered normal in a child of this age. The calculated RI also was higher than that in a.
The spectral waveform produced by flow through the intratesticular arteries characteristically has a low-resistance pattern . The reported normal testicular values in healthy young adults are as follows: RI of 0.48–0.75 (mean, 0.62), PI of 0.7–2.3 (mean, 1.3), PSV of 4.0–19.5 cm/sec (mean, 9.7 cm/sec), and EDV of 1.6–6.9 cm/sec (Fig a). In prepubertal testicles (with a volume of less than 4 cm3), the diastolic arterial flow may not be detectable , and the RI tends to be higher than in pubertal and postpubertal testes (Fig b). These differences may be explained by vasodilatation and increased blood flow in mature testes .
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