title: Role of magnetic resonance imaging for preoperative evaluation of patients with refractory epilepsy.
abstract: OBJECTIVE
  To investigate the magnetic resonance imaging characteristics of patients with refractory epilepsy and the relationship to progression to surgery.
  
  
  METHODS
  Prospective observational study.
  
  
  METHODS
  University teaching hospital, Hong Kong.
  
  
  METHODS
  Patients undergoing preoperative evaluation for epilepsy surgery.
  
  
  METHODS
  Cranial magnetic resonance imaging findings, correlation with electroencephalographic results, and percentage of patients who were considered suitable candidates for surgery.
  
  
  RESULTS
  Structural abnormalities associated with refractory epilepsy in 100 consecutive patients were mesial temporal sclerosis (30%), neocortical sclerosis (23%), vascular malformation (7%), neuronal migration disorders (7%), and tumours (5%). Normal brain scans were found for 28% of patients. Fourteen of 30 (46%) patients with medial temporal lobe lesions at magnetic resonance imaging were suitable candidates for surgery compared with 8/42 (19%) patients with extrahippocampal lesions (odds ratio=3.7; 95% confidence interval, 1.3-10.6; P<0.012).
  
  
  CONCLUSIONS
  Mesial temporal sclerosis was the most common pathology in patients with refractory epilepsy. At the Prince of Wales Hospital, for patients who have undergone a basic magnetic resonance imaging protocol and surface electroencephalography, the result of cranial magnetic resonance imaging is an important determinant for whether patients will undergo surgery.
authors.affiliation: Division of Neurology, Department of Medicine, The Chinese University of Hong Kong, Prince of Wales Hospital, Shatin, Hong Kong.
authors.forename: A C F
authors.initials: AC
authors.lastname: Hui
authors.forename: J M K
authors.initials: JM
authors.lastname: Lam
authors.forename: Y L
authors.initials: YL
authors.lastname: Chan
authors.forename: K M
authors.initials: KM
authors.lastname: Au-Yeung
authors.forename: K S
authors.initials: KS
authors.lastname: Wong
authors.forename: R
authors.initials: R
authors.lastname: Kay
authors.forename: W S
authors.initials: WS
authors.lastname: Poon
mesh_terms: D000293:Adolescent; D000328:Adult; D001921:Brain / Q000473:pathology*; D004569:Electroencephalography; D004827:Epilepsy / Q000175:diagnosis* / Q000601:surgery*; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D011300:Preoperative Care; D012598:Sclerosis