Wr. Widmer et al., Use of radiography, computed tomography and magnetic resonance imaging forevaluation of navicular syndrome in the horse, VET RAD ULT, 41(2), 2000, pp. 108-116
Radiographic evaluation of navicular syndrome is problematic because of its
inconsistent correlation with clinical signs. Scintigraphy often yields fa
lse positive and false negative results and diagnostic ultrasound is of lim
ited value. Therefore, we assessed the use of computed tomography and magne
tic resonance imaging in a horse with clinical and radiographic signs of na
vicular syndrome. Cadaver specimens were examined with spiral computed tomo
graphic and high-field magnetic resonance scanners and images were correlat
ed with pathologic findings. Radiographic changes consisted of bony remodel
ing, which included altered synovial fossae, increased medullary opacity, c
yst formation and shape change. These osseous changes were more striking an
d more numerous on computed tomographic and magnetic resonance images, They
were most clearly defined with computed tomography. Many osseous changes s
een with computed tomography and magnetic resonance imaging were not radiog
raphically evident. Histologically confirmed soft tissue alterations of the
deep digital flexor tendon, impar ligament and marrow were identified with
magnetic resonance imaging, but not with conventional radiography, Because
of their multiplanar capability and tomographic nature, computed tomograph
y and magnetic resonance imaging surpass conventional radiography for navic
ular imaging, facilitating earlier, more accurate diagnosis. Current advanc
es in imaging technology should make these imaging modalities available to
equine practitioners in the future.