Pulsatile Tinnitus with a Dural Arterio-Venous Fistula Diagnosed by Computed Tomography-Angiography
A 43 year-old woman was admitted to hospital with headache of two months' duration and left-sided pulsatile tinnitus that occurred suddenly one month ago and had become severe. She complained of a constant rhythmic sound that beat in synchrony with her heartbeat. The sound became louder in her ear, making it difficult to sleep. On admission, the patient did not have any otologic symptoms such as otorrhea, dizziness and hearing loss except ear-fullness in the affected ear. She had no previous history of surgery, head and neck trauma, or systemic diseases. Based on the results of a questionnaire in which the answers were measured on a 10-point visual analog scale (VAS), her intensity of tinnitus was 7, tinnitus-induced annoyance was 8 and the effects of the tinnitus on her life was 6, showing a high level of discomfort. The tinnitus handicap inventory (THI) was also high, as much as 76. The physical examination revealed no mass in the head and neck, and the otoscopy exhibited no abnormal characteristics of the tympanic membranes. No sound waves were detected by auscultation. The tinnitus sound became weaker when the patient turned her head to the left and when her neck was pressed with the hand. The result of the pure tone audiometric evaluation was 11 dB in the right ear and 18 dB in the left ear. The impedance audiometry produced a Type A curve for both ears. In the tinnitogram, the patient showed pulsatile tinnitus in the left ear. And the sound pressure was 24 dB over the frequency of 1000 Hz. The results of the auditory brainstem response test and distortion product otoacoustic emission test were normal.\nBased on the patient's condition and test results, pulsatile tinnitus was suspected, and CTA was performed as a screening test. In the CTA, a prominent vascular structure was observed along the left tentorial margin, and focal stenosis at the transverse-sigmoid junction was present. Distension of the left occipital artery was also observed (). The CTA findings suggested the possibility of a DAVF, and a 4-vessel CA was performed for the diagnosis.\nAngiography of the left internal carotid artery revealed no abnormal findings in the arterial phase. However, the left external carotid angiogram revealed an enlarged occipital artery. Also, the blood drained to the left transverse sinus and the meningeal vein passing through the transcranial route, extending from the left occipital artery, middle meningeal artery, posterior auricular artery, and superficial temporal artery. The diagnosis of DAVF, fed by the left external carotid artery (ECA), and draining into the left transverse sinus, was therefore made (). Although excessive drainage into the cerebral cortex or brainstem was not observed, transarterial embolization was performed due to the severity of the tinnitus symptoms and the high level of discomfort. First, a 6-Fr guiding catheter was placed through the left ECA to identify the enlarged occipital artery for catheterization. Embolizations with ethylene-vinyl alcohol copolymers (ONYX) were performed to embolize the four feeding arteries. Embolization of the middle meningeal artery was performed to embolize the fifth feeder, followed by transcranial arterial embolization in the proximal portion of the superficial temporal artery. A total of six feeding arteries were embolized. Post-embolization angiography revealed blood flow in fine arteries branching off from the posterior auricular artery and occipital artery. However, the feeders were too small and numerous to perform embolization on. During embolization, the pulsatile tinnitus disappeared, and no post-embolization complications were found. During the outpatient follow-up, the patient did not show tinnitus symptoms but claimed minor fullness in the ear. A THI questionnaire was conducted 3 months postoperatively, and the score for tinnitus-induced discomfort was 0. However, the VAS score for annoyance associated with ear-fullness on the affected side was 2.