Letter to the editor Dural arteriovenous fistula presenting as a seizure mimicking transient ischemic attack: advantages of susceptibility-weighted imaging Dear editor, A dural arteriovenous fistula (DAVF) can occur anywhere within the intracranial dura mater (1). Its manifestations are nonspecific, ranging from mild (e.g. tinnitus, bruit, or headache) to more fatal (e.g. transient ischemic attack, seizure, or intracranial hemorrhage) (2,3). In addition, it is generally less conspicuous on conventional imaging modalities. For these reasons, the diagnosis of DAVF is always challenging. A 56-year-old woman with known hypertension, diabetes, and dyslipidemia presented with transient dysarthria and right hemifacial numbness. On brain Correspondence: Tae-Beom Ahn*, Department of Neurology, Kyung Hee University Hospital, 23 Kyungheedae-ro, Dongdaemun-gu, Seoul 130-872, Republic of Korea. E-mail: ricash@hanmail.net Conflict of interest: None declared. DOI: 10.1111/ijs.12613 magnetic resonance image (MRI) scanning, diffusion-weighted imaging showed no acute lesion, and fluid attenuated inversion recovery (FLAIR) imaging showed abnormal high-signal intensity lesions at the left fronto-parietal juxtacortical area. Gradient echo sequence (GRE) and angiography did not reveal abnormalities suggesting vascular malformation (Fig. 1a–c). Three-weeks later, she again presented to the emergency department with a secondary generalized seizure. In a second brain MRI that included susceptibility-weighted imaging (SWI), the FLAIR findings were nearly identical with those found three-weeks prior. However, in contrast to the prior GRE imaging, the SWI showed distinctly abnormal findings that strongly suggested vascular malformation (Fig. 1d–f). Digital subtraction angiography confirmed a DAVF at the left cavernous sinus. In our case, SWI has higher sensitivity for detecting this vascular abnormality than other conventional sequences, enough to depict lesions that are invisible on T2-GRE images. Prominence of the venous vasculature caused by DAVF can be identified through SWI, because of its high sensitivity to detect and delineate intravascular deoxygenated blood and venous structures (4). Besides DAVF, several other types of vascular malformations can also be visualized with SWI, including developmental venous anomalies, cerebral cavernous malformations, telangiectasia, and Sturge–Weber syndrome (5). We suggest that SWI can be useful in diagnosing many other ambiguous cerebral vascular malformations. Ji Hoon Lee, Sung Hyuk Heo, and Tae-Beom Ahn* Department of Neurology, College of Medicine, Kyung Hee University, Seoul, Korea References 1 Gupta A, Periakaruppan A. Intracranial dural arteriovenous fistulas: a review. Indian J Radiol Imaging 2009; 19:43–8. 2 Oh JT, Chung SY, Lanzino G et al. Intracranial dural arteriovenous fistulas: clinical characteristics and management based on location and hemodynamics. J Cerebrovasc Endovasc Neurosurg 2012; 14:192–202. 3 Kim YW, Kang DH, Hwang YH, Park SP. Unusual MRI findings of dural arteriovenous fistula: isolated perfusion lesions mimicking TIA. BMC Neurol 2012; 12:77. 4 Tsui YK, Tsai FY, Hasso AN, Greensite F, Nguyen BV. Susceptibility-weighted imaging for differential diagnosis of cerebral vascular pathology: a pictorial review. J Neurol Sci 2009; 287:7–16. 5 Lee BC, Vo KD, Kido DK et al. MR high-resolution blood oxygenation leveldependent venography of occult (low-flow) vascular lesions. AJNR Am J Neuroradiol 1999; 20:1239–42. Fig. 1 Brain images at the first admission of the patient [(a) diffusion-weighted image (DWI); (b) fluid attenuated inversion recovery (FLAIR); (c) gradient echo (GRE) images] and at the second presentation three-weeks later [(d) DWI; (e) FLAIR; (f) susceptibility-weighted images (SWI)]. The SWI scan shows distinct abnormalities suggestive of vascular malformation, whereas the GRE and other conventional MR sequences did not. © 2015 World Stroke Organization Vol 10, December 2015, E89 E89