Yield of Brain MRI in Clinically Diagnosed Epilepsy in the Kingdom of Bhutan: A Prospective Study

Abstract

Introduction To report the diagnostic yield of brain MRI and identify clinical associations of abnormal MRI findings among people with epilepsy (PWE) in a neurocysticercosis-endemic, resource-limited setting, and to identify the proportion and putative structural brain causes of drug resistant epilepsy cases. Methods PWE were prospectively enrolled at the Jigme Dorji Wangchuck National Referral Hospital in Bhutan (2014–2015). Each participant completed clinical questionnaires and a 1.5 tesla brain MRI. Each MRI was reviewed by at least one radiologist and neurologist in Bhutan and the U.S.A. A working definition of drug resistant epilepsy for resource-limited settings was given as (a) seizures for >1 year, (b) at least one seizure in the prior year, and (c) presently taking 2 or more antiepileptic drugs (AEDs). Logistic regression models were constructed to test the cross-sectional association of an abnormal brain MRI with clinical variables. Results 217 participants [125 (57%) female; 54 (25%) <18 years old; 199 (92%) taking AEDs; 154 (71%) with a seizure in the prior year] were enrolled. There was a high prevalence of abnormal brain MRIs (176/217, 81%). Mesial temporal sclerosis was the most common finding (n=115, 53%, including 24 children), exceeding the number of PWE with neurocysticercosis (n=26, 12%, including one child) and congenital/perinatal abnormalities (n=29, 14%, including 14 children). The number of AEDs (odds ratio=0.59, p=0.03) and duration of epilepsy (odds ratio=1.11, p=0.02) were significantly associated with an abnormal MRI. Seizure in the prior month was associated with the presence of mesial temporal sclerosis (odds ratio=0.47, p=0.01). 25 (12%) participants met our definition of drug resistant epilepsy with mesial temporal sclerosis (n=10), congenital malformations (n=5), and neurocysticercosis (n=4) being the more frequent findings. Conclusions The prevalence of abnormalities on brain MRI for PWE in resource-limited settings is high due to a diffuse range of etiologies, most commonly mesial temporal sclerosis. Drug resistant epilepsy accounted for 12% of the referral population in a conservative estimation.

The economic burden of epilepsy in Bhutan

“…Epilepsy duration was counted from the time of first seizure onset until the interview date, excluding childhood febrile seizures. Prior research in Bhutan on the aetiology of seizures using brain MRIs identified a high prevalence of mesial temporal sclerosis (53%), neurocysticercosis (12%) and congenital/perinatal abnormalities (14%) .…”

Magnetic resonance imaging and electroencephalography findings in a sample of Iranian patients with epilepsy

“…In a prospective study, Bruno et al ., performed brain MRI in 217 patients with epilepsy and found abnormalities in 81% of patients. [ 22 ] In another prospective study, the brain abnormalities on head computed tomography or MRI are reported in 21% of 366 studied patients with epilepsy. [ 24 ] In the present study, 25.6% of studied patients had abnormal MRI.…”

“…study, among assessed factors (age, duration of epilepsy, and seizures in the last month), only the duration of epilepsy was significantly associated with abnormality on patients MRI and they indicated that longer duration of epilepsy could be a predictor of abnormal MRI. [ 22 ] The difference maybe explained by the different samples and methods, our study was a retrospective study and medical records of patients older than 18 years old were evaluated, but Bruno et al . study was a prospective study on patients in any age, nearly 25 of studied patients in their study were younger than 18-year-old.…”

“…In some previous studies, age, duration of epilepsy, and seizure were associated with abnormalities in MRI or EEG findings in patients with epilepsy. [ 16 22 23 ] The epidemiology of epilepsy is diverse in different countries and regions in Iran, spatially Isfahan; there are no data on abnormalities in MRI and EEG findings and associated factors in patients with epilepsy, so the present study was done to evaluate and compare the frequency distribution of MRI and EEG findings based on demographic variables in a sample of epilepsy patients in Isfahan, Iran.…”

Contraception, pregnancy, and peripartum experiences among women with epilepsy in Bhutan

“…Participants were identified through an existing hospital registry of epilepsy patients at JDWNRH and were enrolled in the larger cohort study including neuroimaging, electroencephalogram (EEG), and often serum neurocysticercosis testing to help confirm the diagnosis and elucidate the potential etiologies of epilepsy. (Brizzi, 2016B, McKenzie, 2016, Bruno, 2017) Data on age, education, employment, seizure characteristics, and AEDs are derived from the initial enrollment evaluation we performed between 2014 and 2016.…”