Feasibility and Safety of Contrast‐enhanced Ultrasound in the Distal Limb of Six Horses

Abstract

Vascular alterations play important roles in many orthopedic diseases such as osteoarthritis, tendonitis, and synovitis in both human and equine athletes. Understanding these alterations could enhance diagnosis, prognosis, and treatment. Contrast-enhanced ultrasound (CEUS) could be a valuable method for evaluation of blood flow and perfusion of these processes in the equine distal limb, however no reports were found describing feasibility or safety of the technique. The goal of this prospective, experimental study was to describe the feasibility and safety of distal limb CEUS in a sample of six horses. For each horse, CEUS of the distal limb was performed after intravenous injections of 5 and 10 ml, as well as intra-arterial injections of 0.5 and 1 ml contrast medium. Vital parameters were monitored and CEUS images were assessed qualitatively and quantitatively for degree of contrast enhancement. None of the horses had clinically significant changes in their vital parameters after contrast medium injection. One horse had a transient increase in respiratory rate, and several horses had mild increases of systolic blood pressure of short duration after intravenous, but not after intra-arterial injections. Intra-arterial injection was possible in all horses and resulted in significantly improved contrast enhancement both quantitatively (P = 0.027) and qualitatively (P = 0.019). Findings from this study indicated that CEUS is a feasible and safe diagnostic test for evaluation of the equine distal limb. Future studies are needed to assess the clinical utility of this test for horses with musculoskeletal diseases.

Clinical utility, dose determination, and safety of ocular contrast‐enhanced ultrasonography in horses: A pilot study

“…Seiler et. al investigated CEUS using custom‐made decafluorobutane to assess blood flow and perfusion in the equine distal limb. Their subjective degree of contrast enhancement was similar for lower (5 mL) and higher (10 mL) intravenous doses, even though the 10 mL resulted in slightly better scores.…”

“…Their subjective degree of contrast enhancement was similar for lower (5 mL) and higher (10 mL) intravenous doses, even though the 10 mL resulted in slightly better scores. It is worth noting that 33% of horses showed no fetlock joint region enhancement after intravenous 5 and 10 mL contrast injections . Compared to our study this percentage was higher than the proportion of animals without qualitative ocular contrast enhancement (22%) but slightly lower than the percentage of eyes without quantitative (39%) contrast enhancement.…”

“…The linear probes utilized in the two studies had a comparable frequency range, and the tissues of interest were approximately in the same depth. Although a different contrast agent has been utilized by Seiler et al, preliminary results of a recent diagnostic accuracy comparison in human focal liver lesions indicated that commercial decafluorobutane is noninferior to SF6 . Since ocular structures are more delicate than parenchyma in the fetlock or palmar pastern region, this factor might have contributed to lack of contrast enhancement in equine eyes.…”

“…Fundamental research regarding CEUS blood flow assessment in sedated horses, birds, and anesthetized and conscious beagles was recently published. The tolerability of CEUS was unknown until Seiler et al examined equine soft tissue structures of the distal limb by intravenous and regional intra‐arterial perfluorobutane. In experimental ophthalmology, CEUS visualized normal vs impaired choroidal perfusion, and correlated with histologic size and vascularity of uveal melanomas in rabbits and mice .…”

“…Globe rupture, lens luxation, lens rupture, retinal detachment, and retrobulbar lesions have been depicted by conventional ultrasonography. Despite being noninvasive, cost‐effective, and widely available, the B‐mode echogenicity is often equivocal which indicates extended modalities (Doppler and contrast imaging), providing additional information on blood flow and perfusion …”