Skull Base 2002; 12(1): 045-052
DOI: 10.1055/s-2002-21572
Copyright © 2002 by Thieme Medical Publishers, Inc., 333 Seventh Avenue, New York, NY 10001, USA. Tel.: +1(212) 584-4662

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Publication Date:
11 March 2002 (online)

IMAGING

Samuel H. Selesnick, Janez Rebol, Linda A. Heier, Jeffrey B. Wise, Philip H. Gutin, Michael H. Lavyne. Internal auditory canal involvement of acoustic neuromas: Surgical correlates to magnetic resonance imaging findings. Otol Neurotol 2001; 22:912-916

Objective: Factors that play a role in the selection of surgical approach for acoustic neuromas include patient health and age, size of tumor, hearing status, and location of tumor in the internal auditory canal (IAC) and the cerebellopontine angle. Deep extension into the IAC makes hearing preservation extremely difficult when a retrosigmoid craniotomy is used, and the best approach is a middle fossa subtemporal route. Modern gadolinium-enhanced magnetic resonance imaging (MRI) can be inaccurate in identifying the presence of tumor laterally in the IAC. This may affect the selection of a surgical approach.

Study Design: This study was a retrospective case review.

Setting: Patients were accrued from a tertiary referral otologic practice.

Patients: From 1997 through 2000, the authors identified six patients who had undergone acoustic neuroma surgery, had adequate imaging and intraoperative data, and demonstrated a lack of correlation between MRI and intraoperative findings of the lateral IAC.

Intervention: The interventions were preoperative MRI of the IAC and surgical resection of an acoustic neuroma.

Main Outcome Measure: Comparison of MRI and intraoperative findings of the lateral IAC were the main outcome measures.

Results: Six patients demonstrated a lack of correlation between MRI and intraoperative findings of the lateral IAC.

Conclusions: Gadolinium-enhanced T1-weighted MRI findings of the depth of penetration into the lateral aspect of the IAC do not always correlate with intraoperative findings and this may have implications in the selection of surgical approaches to acoustic neuromas.

Bernhard Schick, Dominik Brors, Oliver Koch, Maria Schäfers, Gabriele Kahle. Magnetic resonance imaging in patients with sudden hearing loss, tinnitus and vertigo. Otol Neurotol 2001;22: 808-812

Objective: The etiopathogenesis in audiovestibular symptoms can be elusive, despite extensive differential diagnosis. This article addresses the value of magnetic resonance imaging (MRI) in analysis of the complete audiovestibular pathway.

Study Design: Retrospective evaluation.

Setting: Tertiary referral center.

Patients: Consecutive sample of 354 patients (mean age 49 years, range 8 to 86 years) with audiovestibular disorders.

Intervention: Contrast-enhanced MRI of the head with thin-slice investigation of the inner ear, internal auditory meatus, and cerebellopontine angle.

Main Outcome Measure: All MRIs were evaluated by experienced independent investigators. Statistical analysis was performed using the Statistical Package of Social Sciences data analysis 9.0.

Results: MRI abnormalities were seen in 122 of 354 patients (34.5%). The MRIs revealed the following: 4 pathologic conditions (1.1%) of the cochlea/labyrinth, 23 abnormalities (6.5%) at the internal auditory meatus/cerebellopontine angle, 12 pathologic lesions (3.4%) that involved the central audiovestibular tract at the brainstem, 78 microangiopathic changes of the brain (22%), 3 focal hyperintensities of the brain that turned out to be the first evidence of multiple sclerosis in 2 patients and sarcoidosis in 1 patient, and 1 temporal metastasis. Other pathologic conditions, such as parotid gland or petrous bone apex tumors, were unrelated to the audiovestibular symptoms.

Conclusions: This study indicates that contrast-enhanced MRI can be used to assess a significant number of different pathologic conditions in patients with audiovestibular disorders.

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