Magnetic resonance volumetry of the hippocampus in familial spontaneous epileptic cats

A strain of familial spontaneous epileptic cats (FSECs) with typical limbic seizures was identified in 2010. The electroencephalographic features suggested that an epileptogenic zone is present in the mesial temporal structures (i.e., amygdala and/or hippocampus). In this study, visual evaluations and quantitative analyses were performed by using 3D MR hippocampal volumetry in comparing FSECs with age-matched controls. Visual hippocampal asymmetries were seen in 8 of 14 (57.1%) FSECs. The FSEC group showed a significantly higher asymmetric ratio (4.15%) than the control group (0.99%). The smaller side of hippocampal volume (HV) (0.206 cm3) in FSECs was significantly smaller than the mean HV in controls (0.227 cm3). However, the means of left and right HVs and total HVs in FSECs showed no differences because the laterality of hippocampal atrophy was different in each individual. Therefore, since FSECs represent a true model of spontaneous epilepsy, hippocampal volumetry should be evaluated in each individual as well as in human patients. The significant asymmetry of HV suggests the potential for hippocampal atrophy in FSECs.