Causative and Unknown Etiology MRI Abnormalities Both Common in Newly Diagnosed Focal Epilepsy
Younger patients were more likely to have epilepsy-related imaging abnormalities, while older patients were more likely to have incidental abnormalities or those with an unknown relationship to epilepsy.
Anna Bank, MD
Findings from the Human Epilepsy Project observational cohort study showed that more than one-third of patients with a new diagnosis of focal epilepsy had abnormal imaging on MRI, with an even number of epilepsy-related abnormalities and unknown relationship abnormalities. Investigators concluded that the information has clinical implications for patient counseling, prognostication, and management.1
In a cohort of 418 individuals, 35.8% (n = 149) of patients had abnormal imaging, and 5.0% (n = 21) had findings considered to be incidental to the diagnosis of epilepsy. In the overall sample, 18.7% of patients had an MRI-identifiable epilepsy-related imaging abnormality at the time of diagnosis, and 17.0% (n = 71) had abnormalities for which the relationship to epilepsy was unknown. More than half (59.3%; n = 248) of the cohort had no abnormal findings detected.
The study, led by Anna Bank, MD, neurologist, Northwell Health, included patients recruited from 34 sites who underwent 3-Tesla (3T) brain MRI using a standardized protocol. Patients were between 12 and 60 years old, had 2 confirmed spontaneous seizures in the 12 months preceding enrollment, and had either not received treatment or been treated with antiseizure medications for fewer than 4 months preceding enrollment. Additionally, these patients either had a definitive clinical history of recurrent seizures with focal onset or an ictal/interictal EEG showing a focal abnormality, or a focal lesion on MRI.
Among the 149 individuals with abnormal imaging, slightly more than half (50.3%) had exclusively focal abnormalities, while about one-third (32.2%) had diffuse abnormalities, and 17.4% had both focal and diffuse abnormalities. MRI abnormalities correlated with age, as there was an increase observed in older individuals (P = 1.5 x 10-9). This finding remained when participants with foreign tissue lesions were excluded from the analysis (P = 1.47 x 10-9). Notably, those with focal abnormalities were 4.6 years older than those with normal imaging (P = 3.9 x 10-3).
This trend continued throughout the study, as those with enlarged ventricles and diffuse atrophy were 10.4 years older (P = 1.6 x 10-9), and participants with both diffuse and focal abnormalities were 11.4 years older (P = 4.9 x 10-5). When comparing the types of abnormalities, those with epilepsy-related abnormalities were 8.8 years younger than those with abnormalities with an unknown relationship to epilepsy (P = 7.2 x 10-5).
Family history of epilepsy, reported in 31% (n = 131) of the cohort, was not associated with imaging abnormalities (P = .65), focal abnormalities (P = .62), diffuse abnormalities (P = .49), or epilepsy-related abnormalities (P = .22). In the cohort, 15.3% of individuals were between 11 and 18 years old; of those, 40.6% (n = 26) had a family history of epilepsy. Despite this, pediatric patients were not more likely than adults to have a family history of epilepsy (P = .076).
After excluding those with incidental imaging findings (n = 21), and unclassified (n = 11) or uncollected (n = 19) seizure types, findings showed that seizure type was not associated with imaging abnormalities (P = .72) nor epilepsy-related abnormalities (P = .85). Notably, the association between participants’ race and imaging abnormalities was not analyzed because of low numbers of non-White participants. A slightly higher percentage of male participants (44.2%) had imaging abnormalities vs females (30.0%; P = .001).
