Hippocampal abnormalities in an MR imaging series of patients with tuberous sclerosis

Abstract

Background and purpose: Hippocampal abnormalities are known as highly epileptogenic precursor lesions in the general population, primarily manifesting as MTS. The purpose of this study was to evaluate the occurrence of hippocampal abnormalities on MR imaging in patients with TS to explore the possible underlying mechanisms of the abnormalities and to identify the relationship between an abnormal HF and epilepsy.

Materials and methods: We studied MR images and clinical data from 31 patients with TS. The MR imaging protocol was identical for all patients and included tilted coronal images of their temporal lobes. The diagnosis of TSC was made according to established criteria. The HFs of the patients were evaluated from coronal images according to size, morphology, and signal intensity. The data were submitted to statistical analysis, and P values < or = .05 were considered significant.

Results: We found HF abnormalities in 5 patients. Four had typical MTS, and 1 had HIMAL. We found a positive correlation between childhood febrile seizures and MTS in patients with TS. We also confirmed that patients with altered hippocampi had a tendency to exhibit more cortical tubers.

Conclusions: Analysis of this series of patients demonstrated the presence of HF abnormalities, mainly MTS in patients with TS. We also found that the occurrence of febrile seizures during the first year of life appears to be one of the determining factors for MTS development in these patients.

Fig 1.

Patient 18. A and B, Coronal T2-weighted (A) and FLAIR (B) images show the right MTS characterized by hyperintensity, atrophy, and loss of internal architecture. A cortical tuber is observed in the left frontal lobe (arrow).

Fig 2.

Patient 22. Coronal FLAIR image shows the right MTS. Cortical tubers are observed in the bilateral frontal lobes (arrows).