Magnetic resonance imaging findings in epileptic cats with a normal interictal neurological examination: 188 cases.

Raimondi, F; Shihab, N; Gutierrez-Quintana, R; Smith, A; Trevail, R; Sanchez-Masian, D; Smith, P M

Epilepsy is a common neurological condition in dogs and cats. Although an increased likelihood of significant brain lesions with age has been identified in neurologically normal dogs with epileptic seizures, the underlying aetiology of epileptic seizures in cats that present with normal physical and neurological examinations remains unknown. In this cross-sectional study, the authors examined MRI findings in a large population of cats with a normal interictal physical and neurological examination. They hypothesised that age would have an impact on the prevalence of detectable lesions. First, following the guidelines for dogs and in accordance with previous studies, the authors divided the cats into three age groups (aged one year or younger, between one and six, and older than six) and calculated the proportion of cats with a detectable lesion on MRI in these groups. In the first group, 3/32 cats (9.4 per cent) had significant MRI abnormalities that were all consistent with congenital malformation; in the second group, only 5/92 (5.4 per cent) MRI scans were abnormal and in the third group, 15/ 65 (23.1 per cent) cats showed abnormal findings that were predominantly lesions of neoplastic origin. Second, to investigate the impact of age further, data were investigated as a continuous variable using receiver operating characteristic analysis. This indicated an optimal cut-off age of five years, above which MRI abnormalities were more likely, with an increase in the odds of a significant structural lesion increasing by 14 per cent per year.