Doppler e ecobiometria prostática e testicular em cães da raça Boxer / Prostatic and Testicular Doppler and Echobiometry in Boxer Dogs

ABSTRACT

Background: Two-dimensional ultrasound associated to the color and spectral doppler tool allows a complete anatomic and vascular hemodynamic evaluations. The use of these techniques are already well established in Human Medicine, however, in Veterinary Medicine, its use it still relatively recent. Studies on the male reproductive tract, especially in dogs, are scarce and based on small and heterogenic samples. Due to the importance of understanding the normal canine prostate and testes, it was aimed to evaluate the prostate and testes of Boxer dogs by two-dimensional ultrasound associated to color and spectral doppler. Materials, Methods & Results: Five Boxer dogs, ranging from fi ve to seven years old, healthy and presenting a known normal reproductive history were used. Prostatic and testicular volumes were obtained by two-dimensional ultrasonography linear measurements and the volume was calculated using the spheroid formula. The prostatic artery in locations cranial (entering the gland), subcapsular (bordering the capsule), parenchymal (irrigating the prostatic parenchyma) and caudal (leaving the gland) and testicular artery in marginal locations and convoluted spermatic cord were characterized by color doppler ultrasonography through qualitative assessment of flow and measurement of the diameter and the number of pixels formed, and spectral for the morphological characteristics of the spectra and obtain the dopplervelocimetrics parameters peak systolic velocity (PSV), end diastolic velocity (EDV), pulsatility index and resistance index. Data were expressed as mean ± standard deviation and were submitted to ANOVA, followed by Student t test (P < 0.05). The mean prostatic volume was 18.20 ± 0.14 cm³. Right and left testes presented a mean volume of 10.89 ± 0.27 and 10.70 ± 0.41 cm³, respectively. According to the quality of flow, color Doppler signal was classified as intense in cranial and caudal prostatic arteries and along the testicular artery; moderate at subcapsular prostatic artery and little evident in parenchymal prostatic artery. The vessels studied by spectral Doppler showed arterial waveform morphology, with a continuous pattern, with laminar flow different among the studied locations. The testicular artery in both locations and the subcapsular and parenchymal prostatic arteries showed a flow of low resistance and monophasic waveform pattern. The cranial and caudal prostatic arteries showed a biphasic waveform of high resistance. Color and spectral doppler parameters differ at all locations of all vessels, except for PSV and EDV at all locations of the prostatic artery and the pulsatility index and resistance index of the cranial and caudal prostatic arteries. No statistical differences were found between right and left testes, Discussion: Until the present, there are no studies about normal prostatic size in Boxer dogs, mainly using animals within the same group and homogeneous weight. The volume determination is positively correlated to animal weight and it can represent testes development. The prostatic and testicular ultrasound patterns were similar to those already described. The doppler signal could be accurately detect in all studied vessels. The decrease in the vessel diameter collaborates to doppler variation measured by pixels. However, the absence of change in PSV and EDV occurred because there were no changes in cardiac acceleration speed. The presence of a notch is supposed to be due to the difference between subcapsular and parenchymal diameters. The two-dimensional ultrasound associated to Doppler ultrasound may serve as an additional tool in assessing reproductive dogs and that the location of both prostatic and testicular arteries will influence the results.