Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2022 May 11:9:868390.
doi: 10.3389/fvets.2022.868390. eCollection 2022.

Post-mortem Computed Tomographic Angiography in Equine Distal Forelimbs: A Feasibility Study

Chantal Blaettler  1 , Sabine Kaessmeyer  2 , Silke Grabherr  3 , Christoph Koch  4 , Daniela Schweizer  1 , Elke Van der Vekens  1
Affiliations

Post-mortem Computed Tomographic Angiography in Equine Distal Forelimbs: A Feasibility Study

Chantal Blaettler et al. Front Vet Sci. .

Abstract

In-depth understanding of pathophysiological processes occurring in the vasculature of the equine distal limb is of great importance to improve both diagnostic and therapeutic approaches to diseases. To gain further insights, a model allowing high-resolution 3D-visualization of the vasculature is necessary. This pilot study evaluated the feasibility of restoring vascular perfusion in frozen-thawed distal equine cadaver limbs without prior preparation using computer tomographic imaging (CT). Five frozen-thawed, radiographically normal forelimbs were perfused with a lipophilic contrast agent through the median artery and radial vein in three phases (arterial, venous, and arterial-venous combined (AVC) dynamic). For comparison, one additional limb was perfused with a hydrosoluble contrast agent. The CT-studies (16-slice MDCT, 140 kV, 200 mA, 2 mm slice thickness, 1 mm increment, pitch 0.688) were evaluated at 11 specified regions for visualization of the vasculature and presence of artifacts or anatomic variations. The protocol used in this study proved to be feasible and provided good visualization (93.1%) of vasculature with low rates of artifacts. During the different phases, vascular visualization was similar, but while filling defects decreased in the later phases, extravasation worsened in the 2 limbs where it was observed. Subjectively, the best quality of angiographic images was achieved during the AVC dynamic phase. Perfusion with hydrosoluble contrast resulted in significantly lower vascular visualization (74.0%) and higher artifact rates. This study shows that reperfusion of frozen-thawed equine distal limbs with a lipophilic contrast agent allows for high-quality 3D-visualization of the vasculature and may serve as a model for in situ vascular evaluation in the future.

Keywords: PMCTA; cadaver; horse; perfusion; vascular anatomy.

PubMed Disclaimer

Conflict of interest statement

The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.

Figures

Figure 1
Figure 1
Positioning of the limb within the CT-gantry using two stands and a glass container to collect exiting perfusate. For this scan, only the left tube of the perfusion system was connected to the radial vein, allowing drainage of blood and contrast agent through the catheter of the median artery.
Figure 2
Figure 2
(A) 3D-reconstructed post-mortem CT-angiography of an equine distal forelimb after perfusion with a lipophilic contrast agent. The 11 evaluated levels are marked A–K in this reconstruction. (B) Comparison of paired transverse CT images in a bone algorithm (WW/WL: 800/2,000) at each of the 11 evaluated levels (A–K) from post-mortem CT-angiographic studies of two equine distal forelimbs perfused with either lipophilic (LP; left images; limb 1) or hydrosoluble (HS; right images; limb 6) contrast medium. The following vessels were evaluated: 1, palmar digital artery; 2, palmar digital vein; 3, arterial branch of the ergot; 4, venous branch of the ergot; 5, arterial dorsal branch of the proximal phalanx; 6, venous dorsal branch of the proximal phalanx; 7, arterial palmar branch of the proximal phalanx; 8, venous palmar branch of the proximal phalanx; 9, arterial branch of the digital torus; 10, venous branch of the digital torus; 11*, arterial coronary vessel; 12, venous coronary vessels; 13*, arterial dorsal branch of the middle phalanx; 14, venous dorsal branch of the middle phalanx; 15, arterial palmar branch of the middle phalanx; 16, venous palmar branch of the middle phalanx; 17, venous dermal plexus; 18, venous ungular plexus; 19, arterial dorsal branch of the distal phalanx; 20, arterial palmar branch of the distal phalanx; 21, terminal arch; 22, perforating branches; 23, circumflex vessels. *vessels not visible on the displayed transverse images.
Figure 3
Figure 3
Transverse CT images of limb 3 in a bone algorithm (WW/WL: 800/2,000), showing the comparison of vessel-visualization in the (A) arterial, (B) venous, and (C) arterial-venous combined (AVC) dynamic phase scans obtained at the level of the middle aspect of the proximal sesamoid bones (level A). The digital arteries and veins are markedly flattened in the arterial (A) and venous (B) phase, with only the lateral palmar digital vein being more filled on the venous phase (arrow). In the AVC dynamic phase (C) all vessels appear larger and the medial venous branch of the ergot (arrowheads) is more easily identified. Top of the image is dorsal, left is lateral.
Figure 4
Figure 4
Transverse CT images in a bone algorithm (WW/WL: 800/2,000), showing the comparison of extravasation in the (A) arterial, (B) venous, and (C) arterial-venous combined dynamic phase scans obtained of limb 2, the limb which underwent two freezing-thawing cycles, at the level of the metacarpophalangeal joint (level B). While progressive increased extravasation in this limb is evident (arrows; B, C), decreasing the subjective quality of the scans, the degree of extravasation with lipophilic contrast remains clearly lower when compared to the limb perfused with hydrosoluble contrast in Figure 2. Top of the image is dorsal, left is lateral.
See this image and copyright information in PMC

Similar articles

See all similar articles

Cited by

References

    1. Bailey SR, Marr CM, Elliott J. Current research and theories on the pathogenesis of acute laminitis in the horse. Vet J. (2004) 167:129–42. 10.1016/S1090-0233(03)00120-5 - DOI - PubMed
    1. Moore RM, Eades SC, Stokes AM. Evidence for vascular and enzymatic events in the pathophysiology of acute laminitis: which pathway is responsible for initiation of this process in horses? Equine Vet J. (2004) 36:204–9. 10.2746/0425164044877116 - DOI - PubMed
    1. Hlushchuk R, Haberthür D, Djonov V. Ex vivo microangioCT: advances in microvascular imaging. Vascul Pharmacol. (2019) 112:2–7. 10.1016/j.vph.2018.09.003 - DOI - PubMed
    1. Schaad L, Hlushchuk R, Barré S, Gianni-Barrera R, Haberthür D, Banfi A, et al. . Correlative imaging of the murine hind limb vasculature and muscle tissue by MicroCT and light microscopy. Sci Rep. (2017) 7:41842. 10.1038/srep41842 - DOI - PMC - PubMed
    1. Redden RF. A technique for performing digital venography in the standing horse. Equine Vet Educ. (2001) 13:128–34. 10.1111/j.2042-3292.2001.tb00077.x - DOI