Doppler ultrasound of the normal testis in peccary (Tayassu tajacu, Linnaeus, 1758): B-mode, color and spectral doppler imaging

Peccary is an intensely hunted animal in the northeast of the country. Efforts have been established for a better understanding of their reproductive biology. In this context, imaging methods can help identify morphologic and hemodynamic characteristics of the reproductive system of these animals. Eight males peccaries, between 4 to 6 years, were used. The animals were submitted to testicular ultrasound examination (bilateral) B-mode, color Doppler and spectral Doppler. Images of Doppler and color flow Doppler spectral (pulsed) were obtained using an ultrasound machine SonoSite M-turbo coupled to a linear probe multifrequency (12-15 MHz). The testes were accessed in longitudinal and transverse sections. Testicular and epididymis biometric parameters were measured. Using color Doppler we evaluated the distribution pattern of testicular vascular bilaterally. Spectral Doppler was used aligning the sample volume in the pampiniform plexus checking the flow velocity, and resistivity index. The testes showed homogeneous echotexture, echogenicity average (moderately echogenic and uniform standard throughout the parenchyma). The rete testis was viewed as a hyperechoic structure in longitudinal topography (centrally), from the proximal to the distal end. The parameters are expressed as follows: 1) Right testicular length=4.15±0.21cm; 2) Right testicular diameter=2.3±0.31cm; 3) rete testis diameter (right testis)=0.15±0.02cm; 4) Right epididymis head length=1.73±0.31cm; 5) Right epididymis head Diameter= 0.81±0.12cm; 6) Right testicular artery velocity=36.3±1.13cm/s; 7) Right testicular resistivity index 0.67±0.01; 8) Left testicular length=5.07±0.13cm; 9) Left testicular diameter=2.27±0.1cm; 10) rete testis diameter (left testis)= 0.13±0.04cm; 11) Left epididymis head length=2,07±0.08cm; 12) Left epididymis head Diameter= 1,08±0.09cm; 13) Left testicular artery velocity=34.2±1.10cm/s; 14) Left testicular resistivity index 0.68±0.06. The B-mode sonographic pattern was similar to that seen in humans and domestic males, like the dog and the cat, demonstrating reduced vascular flow centrally, and highest volume at the periphery of the testes. The spectral waveform pattern showed a well-defined peak systolic with a slope deceleration similar to that described in domestic animals. No citations were found to peccary testis doppler ultrasound. The resistivity index showed remained stable, characterized by a moderate systolic peak and lower diastolic peak. These findings were also written in humans and domestic animals. There was no statistical difference between the right and left testes compared bilaterally (p>0.05). Thus, these preliminary results allow us to suggest that the testicular flow presented with moderate average velocity, which we attribute probably tortuous vascular plexus associated with thermogenic function. Further studies are being developed and have allowed us to better define these flow characteristics, to associate them with the reproductive profile of reported animal.