Audiometric Protocols for MRI Screening of Acoustic Tumors

Abstract

Objective: 1) Evaluate audiometric protocols and recommend the protocol with best sensitivity and specificity for MRI Screening of acoustic neuroma and meningioma tumors. 2) Determine the clinical “risks” of missing tumors and financial “wastes” in screening nonacoustic tumors and nonpathological cases. 3) Identify decision-making parameters in best-performing protocols.

Method: Retrospective review of 3-year cohort (September 2006 to October 2009) of 1,751 ENT patients who underwent puretone audiometry and acoustic-tumor MRI-screening in a tertiary center. Audiometric protocols were ranked— sensitivity to acoustic tumors; specificity (A and B rates) to nonacoustic tumors and nonpathologies. False negatives indicated clinical risks; false positives determined financial wastes.

Results: No audiometric protocols achieved 100% sensitivity or specificity rates. Only 2 protocols achieved >90% sensitivity rates—the AMCLASS-A-Urben protocol (93.16%) and the Mangham protocol (91.58%). Eleven of 15 protocols for Specificity-A and 12 of 15 protocols for Specificity-B achieved ≥ 50%. Clinical risks were 6.84% to 18.95% while financial wastes were 33.56% to 68.37% for Specificity-A and 31.76% to 66.86% for Specificity-B. Interaural difference parameters indicating highest mean sensitivity rates in the order of ≥ 10dB, ≥ 15dB, and ≥ 20dB, while frequency-comparison parameters were in the order of “two adjacent frequency,” “single frequency,” and “averaged multi-frequency” comparison. Mean specificity patterns were the exact opposite.

Conclusion: Mangham protocol, proposing ≥ 10dB interaural difference averaged 1 to 8khz, is the preferred recommendation (sensitivity 91.58%; specificity-A 44.23%; specificity-B 44.91%). As representation of the local patient population and clinical resource allocation priorities, each center is encouraged to conduct audiometric protocol and symptomatology analysis of its own clinical cohort in deciding diagnostic protocol policy.