THE ROLE OF MAGNETIC RESONANCE IMAGING IN COMPLEX CLINICAL-EEG-IMAGING EXAMINATION OF EPILEPTOGENIC BRAIN TUMORS IN CHILDREN

Abstract

Symptomatic epilepsy is common for patients with supratentorial brain tumors. Among 75 children with supratentorial brain tumors 52 patients had symptomatic epilepsy (69,3%). The most epileptogenic tumors were dysembryoplastic neuroepithelial tumors (DNET), diffuse astrocytomas (DA) and gangliogliomas (GG). In all the cases of DNET and in 4 patients with GG epileptic seizures were the first symptom, and in 4 of 5 cases of DNET seizures were the only clinical sign of tumor presence. DNET, DA and GG looked as iso- or hypointensive lumps on T1-weighted images and as moderate or hyperintensive lesions on T2-weighted and FLAIR images, without mass effect or perifocal edema in cases of DNET and GG. On FLAIR images DNET and GG have so-called “spume-like” (multicystic) structure. Follow up MRI did not reveal significant change in DNET and GG. In one case DNET was noted to be associated with focal cortical dysplasia. In DA it is difficult to distinguish the perifocal edema from tumorous tissue and normal brain tissue, and the growth potential of tumor was slow. The tumors differently cumulate contrast and interpretation of scans with contrast enhancement is ambiguous. Along with DNET (which is epileptogenic in 100% of cases), DA and GG are also epileptogenic brain tumors (seizures occur in 91.7% of cases of DA and in 80% of cases of GG) which should be excluded during diagnosis of drug-resistant focal epilepsy.