![]() All 6 of these patients had small (<1 cm) to medium-sized (1.1–2.9 cm) tumors. Three patients exhibited only intrameatal tumors, and 6 patients had intrameatal tumors with medial extension out of the porous. The ages of these 9 patients (5 men and 4 women) ranged from 40 to 65 years, and the right and left side were involved in 4 and 5 patients, respectively. The most common finding was vestibular schwannoma involving the IAC and/or CPA (n = 9, Table Table2, 2, Figure Figure1). ![]() The Institutional Review Board of Konkuk University Medical Center approved the study (KUH1110056). All patients were administered systemic high-dose steroids (prednisolone 1 mg/kg/day for 4 days, tapered off over the next 10 days). The scanning encompassed the region from the mastoid to the upper edge of the petrous bone. All injections were followed by a saline flush of up to 20 mL. Postcontrast 3D volumetric T1-weighted images (TR/TE, 8.85/3.95 ms FOV, 180 mm flip angle, 12° matrix, 256 × 256 acquiring slice thickness, 1.2 mm reconstructed slice thickness, 0.6 mm) were obtained at 1 minute after an intravenous bolus injection of a standard dose of gadobutrol (Gadovist Schering, Berlin, Germany 0.1 mmol/kg of body weight) through the antecubital vein using a power injector with a rate of 1 mL per second. The parameters for acquiring FIESTA data for cranial nerves on 1.5/3.0 T MRI were the following: TR, 6.1/7.28 ms TE, 1.7/2.30 ms FOV, 180 mm flip angle, 65°/60° matrix, 512 × 256 acquiring slice thickness, 1 mm reconstructed slice thickness, 0.5 mm. ![]() Our IAC MRI protocol included 2-mm thick T1 (TR/TE on 1.5 T and 3.0 T MRI 600/14 ms and 800/2 ms) and T2 (TR/TE 4000/92 ms and 4000/107 ms) weighted axial images, 3D balanced steady-state gradient echo sequence (FIESTA) for cranial nerves, and postcontrast 3D volumetric T1-weighted images (SPGR). MRI was conducted using a 1.5 or 3.0 T MRI (Signa HDx: GE healthcare, Milwaukee, WI) with a phased-array head coil. 4 MRI was performed within 10 days after the onset of sudden hearing loss in all patients, excluding 1 patient who underwent MRI 18 days after the onset of sudden hearing loss (See Results). The mean PTA thresholds in the conversational frequencies (0.5, 1, 2, and 4 kHz) were calculated and used to define each patient's hearing level. No patient had a history of familial deafness or metabolic diseases. 3 All patients had a complete history and underwent a neuro-otological examination. The patients met the clinical diagnostic criteria for SSNHL, which is defined as sensorineural hearing loss of 30 dB or more over at least 3 contiguous frequencies in pure tone audiometry (PTA) that develops within 3 days. The most commonly observed MRI abnormality in patients with SSNHL was vestibular schwannoma, and all of the lesions were small or medium-sized tumors involving the IAC.Ī retrospective analysis of the charts and MRI findings of 291 patients with SSNHL who were admitted to the Department of Otorhinolaryngology-Head and Neck Surgery at tertiary referral hospital from January 2007 to December 2012 was performed. Intralabyrinthine schwannoma, labyrinthine hemorrhage, IAC metastasis, and a ruptured dermoid cyst were each observed in 1 patient. The tumor was small (<1 cm) or medium-sized (1.1–2.9 cm) in these 6 patients. All 9 patients had intrameatal tumors, and 6 of the 9 patients displayed extrameatal extension of their tumors. Vestibular schwannoma involving the internal auditory canal (IAC) and/or cerebellopontine angle was observed in 9 patients. In 291 patients, MRI abnormality, which was considered a cause of SSNHL, was detected in 13 patients. This study aimed to assess abnormal magnetic resonance imaging (MRI) findings in patients with SSNHL and evaluate the value of MRI in identifying the cause of SSNHL.Ī retrospective analysis of the charts and MRI findings of 291 patients with SSNHL was performed. The etiology of sudden sensorineural hearing loss (SSNHL) remains unclear in most cases. ![]()
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