Detection Rate and Radiological Features of Asymptomatic Intracranial Dural Arteriovenous Fistula: Analysis of Magnetic Resonance Imaging Data of 11745 Individuals in the Japanese Brain Check-Up System

Objective: Asymptomatic intracranial dural arteriovenous fistula (DAVF) is a rare disease that is often undiagnosed before symptom onset. The present study aimed to examine the detection rate and radiological features of asymptomatic intracranial DAVF using brain MRI data obtained from the Japanese brain check-up system.Methods: We retrospectively identified 11745 individuals who underwent brain MRI between January 2010 and December 2014. After a routine brain MRI screening, a definite diagnosis was made based on DSA. Data regarding sex, age, disease location, classification type, and treatment method were extracted from the system database and patients’ medical records.Results: Six individuals (0.05%; mean age, 61.0 ± 9.7 years) were diagnosed with definite intracranial DAVF. The intracranial DAVFs were located in the transverse sinus, confluence, and tentorial sinus in 2, 1, and 3 case(s), respectively. Cortical venous reflux was confirmed in four cases (66.7%), and none of the cases had intracranial hemorrhage or venous congestion. All cases had infratentorial lesions and two-thirds were Borden type II/III.Conclusion: The detection rate of asymptomatic intracranial DAVF was 0.05% based on the analysis of MRI data from the brain check-up system. Low-flow shunt and tiny cortical venous reflux were likely missed on MRI.