Duplex Doppler sonographic examinations of the testis in prepubertal boys

This retrospective study of 143 pediatric patients with unilateral acute scrotal disease was done to assess the value of duplex Doppler sonographic examination prior to puberty (110 patients) in comparison to a pubertal group (33 patients) in a pediatric hospital, where the examinations are done by staff radiologists and radiology residents of varying degrees of expertise and experience with Doppler technique. All patients seen during an 18 month period were included. The unaffected side was examined in most patients and served as control. The normal Doppler shift in the center of the prepubertal testis was found to be 0.2 to 0.5 kHz, when using a 5 MHz duplex Doppler probe. With puberty, the Doppler shift increased to 0.5 to 1 kHz. Of 18 patients (10 prepubertal) with testicular torsion, five (three prepubertal) had false-positive Doppler shift. In four of these five cases, faulty placement of the Doppler sample volume cursor was probably the cause. Using a multi-way frequency analysis, puberty was found to have no significant influence on results of Doppler signal (chi square = 0.1346; P = 0.7137). Duplex Doppler sonographic examination is as useful to rule out testicular torsion in prepubertal boys as it is after puberty. Meticulous technique is essential. The opposite side should be examined first and serves as control for the affected one. Results showing no flow in the center of the diseased testis with positive flow in the unaffected one should lead to further clinical action (scintigraphy or surgery).