2009 Radiology Exam - CT/MRI Case 1

Signalment: 5 year old male neutered Greyhound

History:

  • extremely depressed, blind, pyrexic (39.6C)
  • no pupillary light response bilaterally, no menace response bilaterally, no gag reflex, atrophy affecting masticatory muscles

See images below. Click to enlarge.

Observations:

  • study comprises transverse T1-weighted images pre- and post-gadolinium, T2-weighted images and FLAIR images, and sagittal T2-weighted image
  • diffuse thickening of the pachymeninges over the entire cerebrum, most marked on the left
  • lesion is hyperintense in T2-weighted images; marked enhancement after gadolinium administration
  • herniation of the cerebellum
  • signal intensity of muscles appears normal despite history of atrophy

Synthesis:

  • diffuse meningeal lesion suggests meningitis as the principal differential diagnosis; diffuse meningeal neoplasia is less likely
  • cerebellar herniation is evidence of increased intracranial pressure
  • MR lesions are compatible with signs

Management: CSF analysis is indicated as a means of confirming diagnosis; however, increased intracranial pressure is a contraindication to puncture of cerebellomedullary cistern; a lumbar puncture should be considered instead