Abstract
Enhancement of extra-ocular muscles has been reported in cases of orbital pathology in both veterinary and
medical magnetic resonance imaging.We have also observed this finding in the absence of orbital disease. The
purpose of this retrospective study was to describe extra-ocular muscle contrast enhancement characteristics
in a group of dogs with no known orbital disease. Magnetic resonance images (MRI) from dogs with no
clinical evidence of orbital disease and a reportedly normal MRI study were retrieved and reviewed. Contrast
enhancement percentages of the medial, lateral, ventral, and dorsal rectus muscles were calculated based
on signal-to-noise ratios that were in turn determined from hand-traced regions of interest in precontrast,
immediate postcontrast and 10-min postcontrast scans. Comparison measurements were made in the pterygoid
muscle. Contrast enhancement of the extra-ocular muscles was observed in all patients (median contrast
enhancement percentage 45.0%) and was greater than that of pterygoid muscle (median contrast enhancement
percentage 22.7%). Enhancement of the extra-ocular muscles persisted 10 min after contrast administration
(median contrast enhancement percentage 43.4%). Findings indicated that MRI contrast enhancement of
extra-ocular muscles is likely normal in dogs. C 2013 Veterinary Radiology & Ultrasound.
Key words: contrast, enhancement, extra-ocular, muscle, MRI
| Original language | Undefined/Unknown |
|---|---|
| Journal | Veterinary Radiology and Ultrasound |
| DOIs | |
| Publication status | Published - 2013 |