Scrotal US is best performed with a linear 7.5- to 12-MHz transducer. A lower-frequency transducer may be helpful with marked scrotal swelling. Direct scanning with copious acoustic gel is performed most frequently, but a standoff pad may be useful for superficial abnormalities. A towel or the examiner's hand may be used to elevate and support the scrotal sac. In addition to imaging in the longitudinal and transverse planes, it is helpful to obtain simultaneous images of both testes for comparison. Color Doppler is used to evaluate for abnormalities of flow and to differentiate vascular from nonvascular lesions but may be hampered in the younger child by motion artifacts. Attention to appropriate color Doppler settings to optimize detection of slow flow is critical. Power Doppler is a useful adjunct to color Doppler in low-flow states, but it is more sensitive to motion artifacts. The Valsalva maneuver or scanning in the upright position should be performed when evaluating for varicoceles.
Appl Radiol. 2006;35(3):8-17. © 2006 Anderson Publishing, Ltd.