Diagnostic Imaging Modalities for Digital Affections in the Horse

Abstract

The objective of this study was to describe radiographic, ultrasonographic and MRI features of common digital injuries in 40 draft horses collected from Brooke Charity Equine Hospital, Egypt and compares these findings with the post mortem findings for confirmation of imaging findings. Thorough clinical examination, lameness grading, perineural analgesia, radiography, ultrasonography of the palmar/plantar aspect of cannons and phalangeal regions of all limbs was performed using Toshiba just vision, SSA-320A, Japan by 7.5 MHz linear transducer. After euthanasia due to reasons not related to this study, cadaveric limbs underwent magnetic resonance imaging. Fetlock, pastern and foot regions of all limbs were imaged, each region in separated investigation. Images were obtained with a 0.3 T MRI system (Siemens AG 2009, Syngo MR A35, ID: 008). All images were obtained with a brain circular coil (Tx coil). Transverse (axial), sagittal, and dorsal T1-weighted, proton density (PD), T2-weighted (T2-WT), and fast low-angle shot sequence (FLASH) imaging sequences were performed. None of the examined horses was free from MRI abnormalities involving at least two lesions. MRI of the fetlock and pastern regions revealed that 80% of examined horses suffered injuries of both soft and osseous tissues, 16.7% of horses had soft tissue injuries and 3.3% only of these horses had bone and cartilage injuries. In fetlock and pastern regions, seventeen lesions were recorded and described using MRI. All horses had multiple MRI abnormalities. The most frequent MR lesions were digital tenosynovitis (n=13), straight sesamoidean desmitis (n=10), osteosclerosis in the distal part of third metacarpal bone (MCIII) or first phalanx (PI, n=10), adhesions between straight sesamoidean ligament (SSL) and deep digital flexor tendon (DDFT, n=9), oblique sesamoidean desmitis (n=7), cartilage erosions of fetlock or pastern joints (n=7), adhesions between proximal digital annular ligament and DDFT (n=6), DDFTendinitis at pre-navicular part (n=6), proximal digital annular desmitis (n=5), subchondral bone cyst of PI (n=3), and cyst like lesions in PI and PII (n=2).