References
Imaging modalities for the equine distal limb
Abstract
There has been huge investment in computed tomography machines and standing equine magnetic resonance imaging systems across the UK in recent years, with several practices now offering both imaging modalities. It can be difficult to determine which of these imaging modalities is best for imaging the equine distal limb without a good understanding of how each of the imaging systems work practically, and which specific tissues are better evaluated using computed tomography compared to magnetic resonance imaging. It is often not known which tissue is injured when selecting an imaging modality to use. All standing systems, be it magnetic resonance imaging or computed tomography, are affected by patient motion, which can be markedly reduced by the use of general anaesthesia. This article describes the practical features of some of the various systems available for standing distal limb magnetic resonance imaging and computed tomography, and advises on case selection for each modality.
Both computed tomography and magnetic resonance imaging are considered advanced imaging modalities capable of providing three-dimensional imaging of the distal limb. Magnetic resonance imaging is based on the movement of protons, and it is generally considered to be the modality of choice for imaging the anatomic and physiological properties of a patient (Bushberg et al, 2002). Tissues that have very tightly bound protons, such as normal cortical bone and tendon, appear hypointense (black) on magnetic resonance imaging because the lack of proton movement produces very little signal to generate an image. When soft tissues are damaged, there is fluid accumulation as a result of inflammation; as such, protons can move easily and so injured soft tissue shows up as hyperintense (bright/white) on magnetic resonance imaging, contrasting against the black of normal tendon or ligament. Computed tomography relies on x-ray attenuation and relative tissue density (Bushberg et al, 2002) and is considered the modality of choice for cortical bone.
Register now to continue reading
Thank you for visiting UK-VET Equine and reading some of our peer-reviewed content for veterinary professionals. To continue reading this article, please register today.