Comparison of two radiologic methods for measuring the size and growth rate of extracanalicular vestibular schwannomas

摘要: Objective To compare two methods for measuring the size and growth rate of extracanalicular vestibular schwannomas: method recommended in 1995 by American Academy Otolaryngology--Head Neck Surgery (AAO-HNS) maximum cerebellopontine angle (CPA) tumor diameter, i.e., often used radiologic reports. Study design Retrospective clinical study. Setting Tertiary referral center. Patients Fifty-four patients with a diagnosis unilateral schwannoma whose tumors were managed conservatively mean duration 39.8 months (range 12-194 months). Intervention The component was measured use high-resolution magnetic resonance imaging (2- to 3-mm axial slices) at 6- 12-month intervals. Main outcome measures Tumor diameter calculated methods. In AAO-HNS method, image largest selected, anteroposterior (A-P) medial-lateral (M-L) diameters calculated. A-P parallel posterior surface petrous temporal bone, M-L perpendicular it. as square root product these diameters. CPA any direction also measured. Results There no significant difference between rate, although consistently greater than method. strong positive correlation assessing growth. showed correlation, suggesting that portion schwannomas tends enlarge equally both directions. Conclusion is schwannomas. However, because tend grow directions, this suggests preferable.