INTRODUCTION
Antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV) is a necrotising vasculitis that predominantly affects small-size vessels ofany organ. Among AAV, granulomatosis with polyangiitis (GPA) and eosinophilic granulomatosis with polyangiitis (EGPA) frequently affect the eartodevelopvarious otologic manifestations, including external otitis, otitis media, sensorineural hearing loss (SNHL), and facial paresis.1,2However, the lack of specific imaging methods1occasionally hinders early diagnosis of otologic involvement,which is essential for preventing irreversible hearing loss and other long-term complications caused by systemic AAV.
Temporal bone study of GPA shows evidence of vasculitis in the Fallopian canal with and without the clinical presentation of facial paresis.3The stylomastoid artery(SMA) in the Fallopian canalsupplies the posterior half of the external ear canal, tympanic cavity, mastoid, and facial nerve,4which are consistent with frequent sites of otologic involvement in GPA and EGPA. In the present study, using contrast-enhanced, 3D T1-weighted,magnetic resonance imaging (MRI) with gradient-echo sequences (CE-3D-GRE),5,6we tested the hypothesis that this imaging protocol could detect signs of vasculitis in the Fallopian canal, which may cause otologic involvement in AAV patients.