Influence of the position of the foot on MRI signal in the deep digital flexor tendon and collateral ligaments of the distal interphalangeal joint in the standing horse.
BACKGROUND
Hyperintense signal is sometimes observed in ligaments and tendons of the equine foot on standing magnetic resonance examination without associated changes in size and shape. In such cases, the presence of a true lesion or an artifact should be considered. A change in position of a ligament or tendon relative to the magnetic field can induce increased signal intensity due to the magic angle effect.


OBJECTIVE
To assess if positional rotation of the foot in the solar plane could be responsible for artifactual changes in signal intensity in the collateral ligaments of the distal interphalangeal joint and in the deep digital flexor tendon.


METHODS
Six isolated equine feet were imaged with a standing equine magnetic resonance system in 9 different positions with different degrees of rotation in the solar plane.


RESULTS
Rotation of the limb induced a linear hyperintense signal on all feet at the palmar aspect of one of the lobes of the deep digital flexor tendon and at the dorsal aspect of the other lobe. Changes in signal intensity in the collateral ligaments of the distal interphalangeal joint occurred with rotation of the limb only in those feet where mediolateral hoof imbalance was present.


CONCLUSIONS
The position and conformation of the foot influence the signal intensity in the deep digital flexor tendon and in the collateral ligaments of the distal interphalangeal joint.


CONCLUSIONS
The significance of increased signal intensity in the deep digital flexor tendon and in the collateral ligaments of the distal interphalangeal joint should be interpreted with regard to the position and the conformation of the foot.
Spriet
M
M
Department of Surgical and Radiological Sciences, School of Veterinary Medicine, University of California, Davis, California 95616, USA.
Zwingenberger
A
A
D000818:Animals; D017885:Collateral Ligaments / Q000033:anatomy & histology*; D005528:Foot / Q000033:anatomy & histology*; D005552:Forelimb / Q000033:anatomy & histology*; D006736:Horses / Q000033:anatomy & histology*; D008279:Magnetic Resonance Imaging / Q000662:veterinary*; D013710:Tendons / Q000033:anatomy & histology*