Use of high-field and low-field magnetic resonance imaging to describe the anatomy of the proximal portion of the tarsal region of nonlame horses.

The study used high-field and low-field MRI to investigate the anatomy of the proximal tarsal region (near the ankle joint) of 25 healthy, non-lame horses. The purpose of the study is to create a reference that will help veterinarians better interpret MRI images of this area in horses.

Research Objective

• The primary objective of this study was to use both high-field and low-field magnetic resonance imaging (MRI) to comprehensively examine and document the anatomy of the proximal tarsal region (near the ankle) in horses. The researched aimed to provide a frame of reference which would help in the interpretation of MRI images of this area in horses.

Methods

• Twenty-five cadaveric (dead) horse limbs were used in the research. Each horse used in the study had no history of tarsal lameness.
• Both high-field (1.5-T) and low-field (0.27-T) MRIs were used to image the proximal tarsus of each horse.
• The resulting images were used to describe the anatomy and gain measurements of the collateral ligaments of the tarsocrural joint (a joint in the ankle).

Results

• Both long and short components of the lateral and medial collateral ligaments of the tarsocrural joint were successfully identified.
• Some parts of the shorter collateral ligaments were difficult to distinguish on low-field images.
• Generally, ligaments had a low signal intensity; however, certain areas showed increased signal intensity. This was attributed to the magic angle effect which is associated with the orientation of collagen fibres within the ligaments in specific locations.
• The thickness of the subchondral bone of the distal aspect of the tibia was uniform, while the medial trochlear ridge of the talus was generally thicker compared to the lateral trochlear ridge.
• Typically, the thickness of the subchondral bone of the talocalcaneal joint decreased from its proximal to distal aspects.

Conclusions

• The results provided in this study can serve as a reference guide for the interpretation of MRI scans of the proximal tarsal region in horses.
• Such a guide could be particularly useful in clinical settings, improving the accuracy of diagnosis and treatment planning for various tarsal conditions in horses.