Hippocampal Abnormalities in an MR Imaging Series of Patients with Tuberous Sclerosis

H.P.P Gama,R.M.F Valério,C.J Da Silva,A.J Da Rocha,L.Á.L Garcia

doi:10.3174/ajnr.a1972

Abstract

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. 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. 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. 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.

Highlights

AND PURPOSE: Hippocampal abnormalities are known as highly epileptogenic precursor lesions in the general population, primarily manifesting as MTS
ABBREVIATIONS: A ϭ atonic; CNS ϭ central nervous system; CP ϭ complex partial; EEG ϭ electroencephalography; FLAIR ϭ fluid-attenuated inversion recovery; GTC ϭ generalized tonicclonic; HF ϭ hippocampal formation; HIMAL ϭ hippocampal malrotation; LF ϭ left frontal; LO ϭ left occipital; LP ϭ left parietal; LT ϭ left temporal; MTC ϭ magnetization transfer contrast; MTS ϭ mesial temporal sclerosis; N ϭ no; PET ϭ positron-emission tomography; RF ϭ right frontal; RO ϭ right occipital; RP ϭ right parietal; RT ϭ right temporal; SE ϭ spin-echo; SP ϭ simple partial; TS ϭ tuberous sclerosis; TSC ϭ tuberous sclerosis complex; Y ϭ yes Tuberous sclerosis is a neurocutaneous genetically inherited disease characterized by dysplasias and hamartomas that affect multiple organs.[1]
Hippocampal abnormalities are recognized as highly epileptogenic precursor lesions in the general population, and they mainly manifest as MTS, which is the most common cause of partial complex seizures

Summary

Objectives

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. Our aim was to evaluate the co-occurrence of HF abnormalities with structural lesions in a series of patients with TS by using MR imaging

Methods

Results

Discussion

Conclusion