Magnetic resonance microscopy of the equine hoof wall: a study of resolution and potential.
BACKGROUND
Obtaining magnetic resonance images of the inner hoof wall tissue at the microscopic level would enable early accurate diagnosis of laminitis and therefore more effective therapy.


OBJECTIVE
To optimise magnetic resonance imaging (MRI) parameters in order to obtain the highest possible resolution of the structures beneath the equine hoof wall.


METHODS
Magnetic resonance microscopy (MRM) was performed in front feet from 6 cadaver horses using T2-weighted fast spin echo (FSE-T2), and T1-weighted gradient echo (GRE-T1) sequences.


RESULTS
In T2 weighted FSE images most of the stratum medium showed no signal, however the coronary, terminal and sole papillae were visible. The stratum lamellatum was clearly visible and primary epidermal lamellae could be differentiated from dermal lamellae.


CONCLUSIONS
Most structures beneath the hoof wall were differentiated. Conventional scanners for diagnostic MRI in horses are low or high field. However this study used ultra-high field scanners currently not available for clinical use. Signal-to-noise ratio (S/N) increases as a function of field strength. An increase of spatial resolution of the image results in a decreased S/N. S/N can also be improved with better coils and the resolution of high field MRI scanners will increase as technology develops and surface array coils become more readily available.


CONCLUSIONS
Although MR images with microscopic resolution were obtained ex vivo, this study demonstrates the potential for detection of lamellar pathology as it occurs. Early recognition of the development of laminitis to instigate effective therapy at an earlier stage and may improve the outcome for laminitic horses. Clinical MR is now readily available at 3 T, while 4 T, 7 T and 9 T systems are being used for human whole body applications.
Keller
M D
MD
Australian Equine Laminitis Research Unit, School of Veterinary Science, Faculty of Natural Resources Agriculture and Veterinary Science, University of Queensland, Brisbane.
Galloway
G J
GJ
Pollitt
C C
CC
D000003:Abattoirs; D000818:Animals; D005552:Forelimb / Q000033:anatomy & histology; D006724:Hoof and Claw / Q000033:anatomy & histology* / Q000473:pathology / Q000648:ultrastructure*; D006736:Horses / Q000033:anatomy & histology*; D007794:Lameness, Animal / Q000175:diagnosis* / Q000473:pathology; D008279:Magnetic Resonance Imaging / Q000379:methods / Q000662:veterinary*; D012680:Sensitivity and Specificity