Feasibility of transabdominal Doppler sonography for studying uterine blood flow characteristics in cycling gilts

Abstract

Summary Objective: To test for the feasibility of transabdominal Doppler sonography (color, power, pulse wave) to define uterine perfusion characteristics throughout the estrous cycle in gilts. Materials and methods: A total of 15 gilts were synchronized for estrus and scanned in their following spontaneous cycle while being restrained in a purpose-designed mobile crate. To define uterine perfusion characteristics, vessels in between and within uterine cross-sections were imaged and recorded as video sequences to be analyzed by PixelFlux® software for perfused area (Amix), blood flow velocity (vmix) and intensity (Imix) as well as resistance (RIvmix) and pulsatility index (PIvmix). Results: Color Doppler sonography proved to be the only feasible technique, as it was less affected by animal movements than power and pulse wave sonography. As determined by color Doppler sonography, all five parameters determined showed specific patterns through the estrous cycle, i. e. Amix, vmix, Imix were high in proestrus, decreased in estrus and remained low in midestrus and most parts of diestrus; RIvmix and PIvmix with inversely paralleled patterns. Conclusion and clinical relevance: This study has demonstrated that transabdominal color Doppler but not power and pulse wave Doppler sonography is feasible to be performed in crate-restrained gilts for studying uterine perfusion characteristics during the estrous cycle, and that changes of uterine perfusion over the course of the estrous cycle can be clearly followed by color Doppler sonography. Results encourage the use of color Doppler sonography for studying i. e. uterine capacity or uterus related infertility such as for cases of clinically unapparent endometritis.

Feasibility of transabdominal Doppler ultrasonography for studying ovarian blood flow characteristics in cycling gilts

“…This study was performed in conjunction with the investigation on uterine perfusion characteristics of Herlt et al [15] and was approved by the Saxonian Committee for Animal Welfare (No. : TVV 05/14).…”

“…: TVV 05/14). The animals used as well as the general study design were thus identical to the study of Herlt et al [15] and will only be briefly repeated here for main relevant information: A total of 15 reproductively healthy pubertal gilts (German Landrace x Pietrain) with an average age of 253.3 ± 12.2 days and average weight of 148.0 ± 12.1 kg, respectively, were included. Gilts were kept in pens with 2 gilts per pen on partially slatted floors.…”

“…For scanning, gilts were moved into a purpose-designed mobile crate (see Herlt at al. [15]) that was equipped with sliding bars on both sides to allow an easy access to the scanning area, i. e. the right and left inguinal area of the gilts. Feed was dropped onto the floor of the crate in order to additionally distract and thus "immobilize" especially nervous gilts.…”

“…Doppler ultrasonography has, however, never been employed to study perfusion characteristics of the pig's ovaries, which was the aim of this study. However, since power and pulse wave Doppler proved not feasible in the study of Herlt et al [15] and this was the same for ovary scanning with identical constrains in this study, only results generated with color Doppler are presented herein.…”

“…More recently, Brüssow et al [11] have employed Doppler sonography through a minimal invasive laparoscopic approach to study perfusion characteristics of pig fetuses. Most recently, Herlt et al [15] have tested three different Doppler methods (i. e. color, power and pulse wave Doppler) to investigate perfusion characteristics of the uterus of crated cyclic gilts [15]. Color, but not power and pulse wave Doppler, proved feasible for this purpose.…”