Learning objectives
Illustrate the wide variety of epileptogenic pathologies on MRI.
Discuss the MR specific imaging features that help deduce a specific diagnosis withcharacterization of the pathology.
Discuss the importance of each MR sequence in epilepsy imaging.
Background
INTRODUCTION
• An epileptic seizure is defined as “an excessive burst of abnormally synchronized neuronal activity affecting small or large neuronal networks that results in clinical manifestations that are sudden,
transient,
and usually brief’.
• Epilepsy is characterized by recurrent seizures secondary to a predisposition to generate abnormal electrical discharges from cortical grey matter,
and is complicated by subsequent neurobiological,
cognitive,
psychosocial and occupational consequences.
• Up to 10% of the population will have at least one seizure in their lifetime,
but only about 2%...
Findings and procedure details
CAUSES
1.
Mesial temporal sclerosis
2.
Developmental-Diffuse– (poor surgical outcome) Lissencephaly,
Hemimegalancephaly
Focal- (good surgical response) Focal cortical dysplasia,
Heterotopia,Polymicrogyria,
Schizencephaly.
3.Epileptogenic tumors- Ganglioglioma,
Dysembryoplastic neuroepithelial tumor (DNET),
Pleomorphic Xanthoastrocytoma,
Hypothalamic hamartoma,
Desmoplastic infantile ganglioglioma.
4.
Gliosis
5.
Neurocutaneous syndromes – Sturge Weber Syndrome,
Tuberous sclerosis.
6.
Granulomas- Tuberculosis,
Neurocysticercosis.
7.
Inborn errors of metabolism
8.
Hypoxic ischemic encephalopathy
9.
Vascular malformations- Cavernous hemangioma,
Arterio-venous malformations.
10.
Miscellaneous- Rasmussen Encephalitis,
Parenchymal infectious disease.
Periventricular leucomalacia and idiopathic cause.
Hippocampal sclerosis (Mesial temporal sclerosis: MTS)(Fig.
2,3,4)...
Conclusion
·Due to excellent spatial contrast,
MRI is the mainstay of imaging in epilepsy,
determining a definite cause in majority of cases,
especially in medically refractive ones.
·Each specific sequence of MRI has a significant role in identification and characterizing the epileptogenic focus.
Personal information
DEEPAK AGARWAL,
MEDANTA- THE MEDICITY,
GURGAON,
INDIA.
References
Bronen RA,
Fulbright RK,
Spencer DD,
et al.
Refractory epilepsy:comparison of MR imaging,
CT,
and histopathologic findings in 117 patients.Radiology 1996;201: 97-105.
Venkatramana R et al.
MR imaging of epilepsy: Strategies for secccessfulinterpretation.
Radiol Clin N Am 44 (2006) 111-133.
Fitsiori A; Lazeyras F; Seeck M; Nguyen D; Ailianou A; Delavelle J; VargasMI.
Malformations of cortical development of the human brain: A pictorialessay.
J Neuroradiol;39(4):205-17,
2012 Oct
Barkovich AJ,
Kuzniecky RI,
Jackson GD,
Guerrini R,
Dobyns WB (2001)Classification system for malformations of cortical development: update2001....