MRI-identified pathology in adults with new-onset seizures.
OBJECTIVE
To determine the frequency and nature of potentially epileptogenic lesions on MRI in adults with new-onset seizures.


METHODS
We prospectively studied a consecutive series of 993 patients (597 males [61%]; mean [SD] age: 42.2 [18.8] years, range 14.3-94.3 years) who presented to an adult First Seizure Clinic over a 10-year period. The MRI scans, performed clinically on 3- and 1.5-tesla scanners, were reviewed for their diagnostic yield, nature of abnormalities, and their association with abnormal electrical activity on EEG.


RESULTS
MRI scans were acquired in 764 patients (77%); potentially epileptogenic lesions were detected in 177 (23%). The frequency of potentially epileptogenic lesions was higher in patients who were diagnosed as having an epileptic seizure (28%) than in those with a nonepileptic event (8%) (p < 0.001), and highest in those who had focal-onset seizures (53%) (p < 0.001). The most common lesion type in patients with focal seizures was gliosis or encephalomalacia (49%). Other common lesion types were tumors (15%), cavernomas (9%), and mesial temporal sclerosis (9%). Abnormal MRI and EEG were concordant in 18% of patients, with EEG being normal in 55% of patients with epileptogenic lesions.


CONCLUSIONS
MRI reveals potentially epileptogenic lesions in a minority of patients with a newly diagnosed seizure disorder. Lesions are most common in patients who have experienced focal seizures. The presence of a potentially epileptogenic MRI lesion did not influence the chance of having an abnormal EEG.
Melbourne Brain Centre, Department of Medicine, The Royal Melbourne Hospital and the Epilepsy Research Centre, Department of Medicine, The University of Melbourne, Australia.
Tahir
T
Hakami
Anne
A
McIntosh
Marian
M
Todaro
Elaine
E
Lui
Raju
R
Yerra
K Meng
KM
Tan
Chris
C
French
Simon
S
Li
Patricia
P
Desmond
Zelko
Z
Matkovic
Terence J
TJ
O'Brien
D000293:Adolescent; D000328:Adult; D017668:Age of Onset; D000368:Aged; D000369:Aged, 80 and over; D002648:Child; D015331:Cohort Studies; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D012640:Seizures / Q000175:diagnosis* / Q000453:epidemiology* / Q000473:pathology; D055815:Young Adult