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Reversible magnetic resonance imaging abnormalities in dogs following seizures
L M Mellema1, P D Koblik, G D Kortz
1Veterinary Medical Teaching Hospital, School of Veterinary Medicine, University of California-Davis, 95616, USA.
Abstract:
Reversible magnetic resonance (MR) imaging lesions have been described in humans following seizures. This condition has not yet been reported in animals. This paper describes reversible abnormalities identified in 3 dogs using MR imaging that was performed initially within 14 days of the last seizure and follow-up imaging that was performed after 10 to 16 weeks of anticonvulsant therapy. All three dogs had lesions in the piriform/temporal lobes, characterized by varying degrees of hyperintensity on T2-weighted images and hypointensity on T1-weighted images. In one dog, contrast enhancement was evident. On reevaluation, partial resolution occurred in all 3 dogs. In a fourth animal with an olfactory meningioma, similar appearing lesions in the temporal cortex and right and left piriform lobes were identified after seizure activity. A surgical biopsy of the temporal cortex and hippocampus was performed and edema, neovascularization, reactive astrocytosis, and acute neuronal necrosis were evident. These histologic findings are similar to those reported in humans with seizures. Recognizing the potential occurrence of reversible abnormalities in MR images is important in developing a diagnostic and therapeutic plan in canine patients with seizures. Repeat imaging after seizure control may help differentiate between seizure-induced changes and primary multifocal parenchymal abnormalities.
Insights
Reversible magnetic resonance (MR) imaging lesions were observed in dogs after seizures, a finding previously unreported in animals. Follow-up MR imaging showed partial resolution, suggesting these changes may be temporary.
Area of Science:
- Veterinary Neurology
- Diagnostic Imaging
- Comparative Neurology
Background:
- Reversible magnetic resonance (MR) imaging lesions are known in humans post-seizure.
- Such findings have not been previously documented in veterinary medicine.
- This study investigates similar reversible MR imaging abnormalities in canine patients.
Observation:
- Three dogs exhibited reversible MR imaging lesions in the piriform/temporal lobes within 14 days of their last seizure.
- Lesions appeared as T2-weighted hyperintensity and T1-weighted hypointensity, with one case showing contrast enhancement.
- A fourth dog with an olfactory meningioma also showed similar lesions post-seizure.
Findings:
- Follow-up MR imaging after 10–16 weeks of anticonvulsant therapy revealed partial resolution of lesions in all three dogs.
- Histopathology from the fourth dog revealed edema, neovascularization, reactive astrocytosis, and neuronal necrosis, consistent with human seizure-related changes.
- These findings suggest that some MR imaging abnormalities following seizures in dogs may be transient.
Implications:
- Recognizing reversible MR imaging changes is crucial for accurate diagnosis and treatment planning in dogs with seizures.
- Repeat imaging after seizure control can help differentiate seizure-induced abnormalities from primary brain lesions.
- This research provides valuable insights into the neuroimaging manifestations of seizures in canines.