Although pyometra is a common disease, the mechanisms that determine cervical opening remain unknown. Knowing that the vascular structures are crucial in pathophysiology, it was observed need for hemodynamic studies assessing uterine artery of female dogs with pyometra and its relation to the neck opening. Thirty-five female dogs were selected and separate into three groups: control group (CG) (n = 12), open-cervix pyometra group (OCG) (n = 11) and closed-cervix pyometra group (CCG) (n = 12), with the objective of evaluating and comparing the hemodynamic changes of the uterine artery [peak systolic velocity (PSV), end diastolic velocity (EDV), and resistance index (RI)] in female dogs with open- and closed-cervix pyometra and correlate them with measurements of uterine diameter (UD) and endometrial thickness (ET). The correlation analysis showed that, with the exception of PSV, the hemodynamics indices were associated with UD and ET, presenting a moderate and positive correlation between UD and EDV (r = 0.62; P<0.01), a moderate and negative correlation between UD and RI (r =-0.68; P<0.01) and also moderate and negative correlation between ET and RI (r = -0.62; P<0.01). These results suggest that alterations of uterine artery hemodynamics are similar in dog females with open- or closed-cervix pyometra, although the UD and the ET can influence in the uterine perfusion.

The purpose of this article is to review the literature on the essential technical aspects of implementing the pulsed Doppler, as part of the teachings to their use in the diagnosis of changes in the canine reproductive system. A narrative review was carried out, using scientific articles, monographs, theses and dissertations published and available in online databases: Periodical Capes (Coordination for the Improvement of Higher Education Personnel), SciELO (Scientific Electronic Library Online) and Google Scholar, in addition to specific books on the topic. Two-dimensional ultrasound has been widely used in medicine since 1942, leading to advancements in disease identification and subsequent prognosis. In terms of vascular assessment, Doppler ultrasound is used to evaluate the blood flow inside the vessel, its direction, and hemodynamic pattern. Among all types of Doppler ultrasound, the Color Doppler (CD), Power Doppler (PD), and the Pulsed-wave Doppler (PW) are commonly used in the identification of abnormalities through ultrasound flow imaging and the analysis of hemodynamic indices: peak systolic velocity (PSV), end diastolic velocity (EDV), resistance index (RI), and pulsatility index (PI). To accurately estimate these hemodynamic indices, however, it is essential to know the technical adjustments and parameters such as the pulse repetition frequency (PRF), size of the sample volume (Gate), angle of insonation, gain, baseline, and wall filter, which need to be corrected to avoid technician derive artifacts such as aliasing, signal absence, and mirror imaging. In medicine, the use of Doppler Mode in reproductive functions is already well established, but its use in veterinary medicine is still a subject of recent studies.

Given the importance of the reproduction field combined with the use of the Pulsed-Wave (PW) ultrasound in the clinical routine, this study aims to review the application of this diagnostic method in the reproductive tract of females and males of the canine species. A narrative review was carried out by using scientific articles, monographs, dissertations and thesis published and available in online databases: Periodical Capes (Coordination for the Improvement of Higher Education Personnel), SciELO (Scientific Electronic Library Online) and Google Scholar, in addition to specific books on the topic. In female dogs, Doppler ultrasound can be used to evaluate hemodynamic conditions in the estrous cycle (e.g. estimating day of ovulation and fertility, diagnosing early pregnancy, abnormalities, and fetal stress, thus ensuring greater obstetric safety) and identification of diseases, thereby avoiding unnecessary surgical interventions. In male dogs, however, Doppler ultrasound is mainly used in vascular evaluations in order to identify hemodynamic changes due to occurrence of benign prostatic hyperplasia (BPH), most common disease of the prostate and in the assessment of testicular arteries to better understand spermatogenesis and diseases that affect the testicle. In this review, we demonstrate that the use of Doppler mode ultrasound, especially the PW, allows dynamic analysis in clinical examination and complements important information in the diagnosis and treatment of different reproductive disorders in dogs.

Association between the -420 C> G polymorphism (rs1862513) in the human resistin gene and obesity in a sample of the Brazilian populationAssociação entre o polimorfismo -420 C>G (rs1862513) no gene da resistina humana e obesidade em uma amostra da população brasileira