LAUSR

Background Patients with intracranial arteriovenous malformations (AVMs) are at increased risk of seizures. Objective To identify MRI characteristics of unruptured intracranial AVMs associated with seizures at presentation. Materials and methods A retrospective review was completed of patients diagnosed with unruptured intracranial AVMs on MRI between January 1, 2000 and December 31, 2016. Two blinded reviewers assessed demographics, lesion locality, and imaging and architectural characteristics of AVMs and surrounding parenchyma, including, but not limited to, AVM location, venous drainage pattern, venous varix, thrombosed venous varix, long draining vein, AVM-related gliosis, peri-AVM edema, and peri-AVM T2* signal. Findings were statistically analyzed for correlation with seizure using Student’s t-test for continuous variables and Χ2 test for categorical variables. Results Of 165 included patients, 57/165 (34.5%) patients were imaged as part of an investigation for seizures. Patients with seizures more commonly had peri-AVM edema (36.8%, compared with 11.1% of non-seizure patients, p<0.0001), peri-AVM T2* blooming (28.1% vs 7.4%; p=0.029), a venous pouch/varix (61.4% vs 31.5%, p=0.0003), long draining vein (91.2% vs 55.6%, p<0.0001), and larger size based on Spetzler-Martin grade categorization (p=0.006). By location, AVMs located in the frontal lobe, primary motor cortex, and primary sensory cortex were associated with seizures (p=0.004, p=0.001, and p=0.006, respectively); temporal lobe location was not associated with seizures (p=0.459). Conclusions Certain MRI characteristics of unruptured intracranial AVMs are associated with seizures. Such correlations may assist in identifying the pathophysiological mechanisms by which AVMs cause seizures.