CT/MRI Society Case of the Month
May 2006
Sponsored by Eklin Medical Systems
Patient Identification Number: CTMRSOC1
Patient Surname Code: CTMRSOC
Patient First Name Code: PEASE
Accession Number: MAY06
Contributor: Anthony Pease
Contributor’s Affiliation: North Carolina State University
Species: Canine
Breed: Toy Poodle
Age at exam: 11 years old
Gender: Female neutered
Presenting signs and pertinent history: Patient presented to the emergency service after falling off the couch onto a tiled floor. The patient lost consciousness and was not breathing when found by the owner. Resuscitation by the owner was successful. The referring veterinarian administered dexamethasone and atropine intravenously prior to referral.
Clinical/Neuro exam findings:
Mentation: Stuporous
Posture: Laterally recumbent
Gait: Vestibular ataxia – marked, non-ambulatory
Postural reactions: absent in all 4 limbs
Cranial nerves: Menace absent in both eyes, papillary light reflexes normal bilaterally, bilateral ventral strabismus, horizontal nystagmus
Spinal reflexes: Normal
Hyperesthesia: Negative
Panniculus: normal
Relevant Laboratory data:
Elevated:
Glucose (139; reference range = 73-116 mg/dL)
BUN ( 29, reference range = 8-27 mg/dL)
Cholesterol (325, reference range = 138-317 mg/dL)
ALT (193, reference range 16-73 IU/L), CK (1660, reference range = 48-380 IU/L).
Neutrophilic leukocytosis with a left shift (21,864 segmented neutrophils, reference range = 2,529-12,876 cells/µL and 233 bands, reference range = 0-25 cells/µL)
Leucopenia (0 cells/µL, reference range = 480 – 3,762 cells/µL)
Monocytosis (1163, reference range = 49-912 cells/µL).
Primary clinical rule-out pre imaging: Central vestibular and multifocal/diffuse forebrain lesion
Modality: MR
Manufacturer: Siemens Symphony
Model/Field Strength: 1.5 T
Sequences Acquired:
Transverse Proton Density
Transverse T2
Transverse FLAIR
Transverse T1
Transverse T2 Gradient Echo
Sagittal T2
Transverse T1 post contrast medium
Sagittal T1 post contrast medium
Dorsal T1 post contrast medium
CT/MR Findings:
There is mild bilateral hydrocephalus present. In addition, the dilation of the lateral ventricles are asymmetric and more severely dilated on the left side. There is a large well demarcated region of primarily white matter T2 hyperintensity in the lateral aspect of the cerebrum spanning the frontal, rostral temporal and right parietal cortex. There is mild compression of the adjacent internal capsule and a subtle midline shift to the left. There is no evidence of internal capsule edema, but the adjacent pathology may be contributing, at least in part to the relatively smaller right lateral ventricle. Caudally, there is a region of increased T2 signal intensity in the right lateral aspect of the occipital lobe. The occipital lesion does not appear to communicate with the parietal lesion.
There is T2 hyperintensity and contrast medium enhancement of the right temporalis musculature, immediately adjacent to the region of brain edema. In addition, there is an ill-defined region of decreased T1 signal intensity in the region of increased T2 intensity of the right frontal lobe. With contrast medium administration, the region of low signal intensity has a small blush of contrast medium enhancement, immediately adjacent to the extracranial muscle enhancement. No evidence of a calvarial fracture is identified.
There is there a focal region of increased signal intensity best identified on the sagittal T2 weighted image in the most caudal ventral aspect of the cerebellum. This lesion is likely secondary to cerebellar edema.
The gradient echo sequence identifies multiple areas of signal voids due to increased magnetic susceptibility secondary to hemoglobin. This occurs with acute hemorrhage. These multifocal areas are within the right frontal lobe and the right aspect of the thalamus.
The MRI appearance is most consistent severe head trauma with subdural and intraparenchymal hemorrhage and edema. The cerebellar edema as well as the frontal lobe edema and hemorrhage would account for the clinical signs including ataxia, recumbency and vertical nystagmus.
CT/MR Assessment:
Severe head trauma and hemorrhage without evidence of displaced fracture fragments of the calvaria. In addition, there is bilateral, assymetric hydrocephalus, which is likely a congenital anomaly.
Post Imaging Management:
The patient was supported with intravenous fluids, antibiotics and dexamethasone SP. Approximately 4 days after presentation, the patient became less responsive and thoracic radiographs revealed a cranioventral alveolar lung pattern. The primary differential diagnosis for this lesion was bronchopneumonia, so the patient was started on enrofloxacin and placed in an oxygen cage. The next day the patient experienced respiratory arrest and the owners elected against resuscitation.
Outcome:
The patient died and necropsy examination was performed.
Final Diagnosis based on all diagnostic tests and outcome:
Necropsy findings:
Moderate subdural hemorrhage
Focal, moderate, cerebral hemorrhage of the right occipital lobe
Multifocal, moderate acute hemorrhage of the right thalamus
Regional, moderate, subacute to chronic vascular proliferation, right thalamus
Focal, mild acute hemorrhage, cerebellar white matter
Regional, moderate, acute white matter degeneration, brain stem
Multifocal to coalescing, marked intramuscular hemorrhage of the temporal muscles
Fracture of the right parietal and right temporal bones
Multifocal hypoplasia, left frontal/parietal, and left and right temporal/occipital bones.
Comments:
This case was presented to illustrate the usefulness of gradient echo sequences to detect hemorrhage as well as the difficulty of MRI to detect subtle fractures of thin bone (like the skull) if the fractures are minimally displaced.