MRI case presented as part of the 1997 A.C.V.R. oral certification examination: computed tomography/magnetic resonance imaging elective

Mattoon JS, Walker MA.

Vet Radiol Ultrasound 1998;39:154-155.

Signalment

Canine mixed breed, female, 14 years of age.

History

Depressed; decreased air passage through left nares; left exophthalmos and anisocoria; blind in the left eye and the left eye does not response to light.

MRI Examination

T1 weighted dorsal images were made of the head (Fig. 1A). Subsequently, contrast enhanced T1 weighted dorsal images were made (Fig. 1B). (Only select images for publication are provided. The candidate was provided with mul- tiple multiformat images, including transverse images.)

MRI Findings

A partially contrast-enhancing mass of the left periorbital region and the mid-to-caudal left nasal cavity is present. The mass extends into the left olfactory and frontal regions of the brain. The mass is apparently crossing midline caudally into the right nasal cavity.

Diagnosis

Malignant neoplasia, probably a nasal adenocarcinoma extending from the nasal cavity into the left periorbital re- gion, through the cribriform plate into the rostral portion of the brain.