Objective: The aim of the present study was to verify the diagnostic validity of low-field magnetic-resonance-imaging (MRI) findings in septic diseases of the foot region following penetrating sole injuries caused by nails.
Materials and methods: MRI examinations were performed in 10 horses with injuries in the foot region. The diagnostic findings were validated by conventional methods (clinical, surgical, radiological, sonographic, and computed tomographic findings and/or post-mortem histological examination).
Results: Navicular bone involvement was revealed most accurately, with a high degree of predictability, and was best detected by fat-suppressed T2 or short-TI inversion recovery (STIR) sequences. MRI examinations of defects in the deep digital flexor tendon showed a high level of sensitivity, but these findings were less specific than changes to the navicular bone. They could be best reproduced in transverse T2-weighted fast spin echo sequences (T2w FSE). The penetration tract was recognisable in all cases and in all planes, and the T2w FSE proved to be very suitable for diagnosis. Septic bursitis was revealed least accurately by MRI. Bursal disease was best recognised in the sagittal plane.
Conclusion and clinical relevance: MRI is a reliable method for confirming the diagnosis of diseases in the foot region after injuries caused by foreign bodies, particularly nails. A transverse T2w FSE is best suited for demonstrating a penetration tract and tendon damage. Visualisation of the penetration tract and secondary reactions of the navicular bone are crucial for diagnosing bursitis. Fat-suppressed sequences can clearly show bone involvement when the penetration tract has not reached the bone. The cases described illustrate that MRI is an appropriate method for evaluating puncture wounds in the foot region. Only MRI allows for intravital assessment of various structures within the hoof capsule. This information is essential for deciding upon targeted therapy while avoiding unnecessary therapies.
Keywords: MRI; hoof; penetrating injury; pododermatitis.