Doppler evaluation of renal resistivity index in healthy conscious horses and donkeys

Imaging of the Urinary Tract

This article provides a comprehensive review of imaging techniques used to evaluate the equine urinary tract. This overview includes officially recognized modalities and new applications reported in the most current literature. Technical aspects and indications for use of endoscopy and ultrasonography are highlighted. Normal endoscopic and ultrasonographic appearance of the upper and lower urinary tract is described, with characterization of common abnormalities found in patients with hematuria, stranguria, and renal failure. Visual examples of several pathologic conditions from clinical cases are provided. An outline of the main features, potentials, and limitations of radiography, nuclear scintigraphy, and computed tomography is provided.

Ultrasonographic study of hemodynamics and CEUS in the rhesus monkey kidney

Nonhuman primates share many developmental similarities with humans. As the world has recognized the rhesus monkey as a standard experimental monkey, studies of rhesus monkey are very important and essential. The purpose of this study was to use gray-scale ultrasound, color Doppler flow imaging (CDFI), and contrast-enhanced ultrasound (CEUS) to study the ultrasound appearance of adult healthy rhesus monkey kidneys and to investigate the relationship between renal ultrasound manifestations and body weight, gender, and the left and right kidneys. Thirty adult healthy rhesus monkeys were studied in the experiments. The size of the kidney and the length and diameter of the renal artery were measured. The peak systolic velocity (PSV), end diastolic velocity (EDV), and resistance index (RI) of the renal artery and intrarenal arteries were measured by CDFI. In CEUS, the time-intensity curve (TIC) was used to obtain microvascular perfusion parameters. There were significant differences in renal size, diameter and length of the renal artery, and hemodynamics of the renal arteries between the different weight groups. In CEUS, there were significant differences in area under curve (AUC), time from peak to one half (THP), intensity peak (PI), time to peak (TTP), mean transit time (MTT), and wash-in-slope (WIS) between the different weight groups. There were no statistical differences between genders or the left and right kidneys. Our study provides valuable reference data for the studies of the kidney and indicates that CEUS can be used to evaluate renal perfusion in rhesus monkeys.

Renal Resistive Index as A Potential Indicator of Acute Kidney Injury in Horses

Reliable and simple tests are constantly being sought to enable the quick detection of acute kidney injury in humans and animals. Diagnosis of subclinical AKI in horses, mainly in field practice, is difficult. An ultrasound scan is a routine test performed when kidney disease is suspected. The aim of the study was to establish the value of the renal resistive index (RRI) in intrarenal arteries in horses with clinical AKI and compare it to that of healthy horses. The second goal was to determine whether potentially nephrotoxic agents can influence RRI. The kidney ultrasonography examination was performed in 30 healthy horses, 11 horses with AKI and 30 horses at risk for AKI (10 colic horses, 10 horses receiving gentamicin and 10 horses receiving NSAIDs). RRI values were measured using pulsed-wave Doppler. Differences in RRI between groups were observed only in the right kidney. Horses with AKI had significantly higher RRI values compared to healthy horses. In the risk group, there was no effect of potentially nephrotoxic agents on the RRI value. RRI value in horses seem to be lower than in other species. The increase in this parameter in horses with AKI affected only one kidney and these values did not reach values obtained in other species. The clinical application of this method in non-cooperating animals remains questionable, and therefore RRI Doppler ultrasonography of blood flow in the intrarenal arteries may have poor clinical utility as a diagnostic tool in the diagnosis of AKI in horses.

Transabdominal Renal Doppler Ultrasound in Healthy Adult Holstein-Friesian Cows: A Pilot Study

Simple Summary

Knowledge of the physiological renal blood flow in cattle is essential for interpretation of Doppler ultrasound. In this paper, we describe a protocol for obtaining the renal Doppler parameters resistive index (RI) and pulsatility index (PI) in a systematic ultrasound evaluation of the kidney in cattle and provide preliminary reference values for healthy adult Holstein-Friesian cows.

Abstract

There is a notable lack of reference values for the renal resistive indices in the bovine kidney. Ultrasound (US) Doppler evaluation of these indices is a powerful, non-invasive technique for assessing, monitoring and diagnosing renal diseases in humans and other animals (e.g., small animals and horses). The aims of the present study were to establish a protocol for renal Doppler US in adult healthy Holstein-Friesian cows and to provide reference values for the renal resistive index (RI) and pulsatility index (PI). In cattle, the right kidney is always visible through a right abdominal window. Nevertheless, the left kidney is rarely accessible by transabdominal ultrasound. Doppler evaluation of the kidneys via a transabdominal approach is possible when accessible, but measurements can only be made in the larger vessels at the renal hilum. Normal RI and PI values were respectively 0.49 ± 0.07 and 0.70 ± 0.15 for the right kidney and 0.53 ± 0.05 and 0.79 ± 0.11 for the left kidney. We suggest an upper cut-off value for the RI of 0.63 and for the PI of 1.00 in healthy Holstein-Friesian cows. This is the first report describing normal values for the renal RI and PI in cattle that may be useful in future studies for characterizing different bovine pathologies that affect the renal parenchyma.

Changes in Renal Resistive Index Values in Healthy Puppies during the First Months of Life

The purpose of this study is to establish renal resistive index (RRI) of normal kidneys in puppies aged from newborn to 20 weeks of age and to determine the age at which RRI reaches adult dog values. Six healthy adult intact beagles and six puppies from 1 day after birth to 20 weeks of age were used. In the adult dogs, the ultrasonographic scans were performed once, and in the puppies, the ultrasonographic studies were performed on the first day after birth and at 1, 2, 3, 4, 6, 8, 12, 16, and 20 weeks of age. RRI was obtained at the interlobular and arcuate arteries in each kidney. There were no statistical differences between the RRI values obtained between the right and left kidney nor between intrarenal arteries (interlobar and arcuate). The RRI was the highest during the first weeks of life, after which it declined gradually with increasing age reaching adult dog values at 12 weeks of age. In conclusion, the normal mean RRI is age dependent in dogs. Twelve weeks can be regarded as the age at which adult mean RRI criteria can be applied to puppies.