Hearing preservation and vestibular schwannoma: intracochlear FLAIR signal relates to hearing level.

OBJECTIVES

This study aimed to evaluate the relationship between cochlear signal on fluid-attenuated inversion recovery (FLAIR) magnetic resonance imaging (MRI) sequences and hearing in patients undergoing hearing preservation surgery for vestibular schwannoma (VS) and to demonstrate a new classification system to be used in imaging evaluation of patients with VS.

METHODS

A search of archived surgical cases at a single institution between January 1, 2006, and January 1, 2012, revealed 51 patients who underwent hearing preservation surgery for VS. Tumor size, patient age and sex, and preoperative and postoperative pure-tone average (PTA) and speech discrimination score (SDS) were recorded. Cochleae on the affected side were examined on preoperative FLAIR sequences and classified as limited hyperintensity (LH) or extensive hyperintensity (EH).

RESULTS

Mean patient age was 51 years, and mean tumor size was 1.3 cm. Preoperative FLAIR sequences were classified into LH (n = 36) and EH (n = 15) categories. Preoperative PTA and SDS were 29.5 dB (SD, 16.7), 90% (SD, 14) and 40.6 dB (SD, 13.8), 80% (SD, 25) for LH and EH, respectively. On univariate analysis, preoperative PTA was superior in the LH group (p = 0.04). There was a trend toward superior preoperative SDS and postoperative PTA in the LH group, but these differences were not statistically significant (p = 0.08 and p = 0.06, respectively).

CONCLUSION

The current study is the first to demonstrate a distinct association between cochlear FLAIR signal and pretreatment hearing levels in patients with VS. A new classification system for evaluating cochlear FLAIR signal is proposed. Improvement in FLAIR sequences will allow further investigation of this association.