Assessment of Vestibular Schwannoma Growth: Application of a New Measuring Protocol to the Results of a Longitudinal Study

This study pertains to a group of 44 patients with unilateral vestibular schwannoma who did not undergo surgery. Prospectively, the dimensions of the tumor were depicted at regular intervals by means of magnetic resonance imaging and then judged independently by an otolaryngologist and a neuroradiologist. Retrospectively, the size of the tumor was quantified by measuring the maximum surface of the lesion in the axial plane. The retrospective surface measurements confirmed the assessments made in the prospective part of the study: growth in 18% of the patients and shrinkage in 7%; 75% remained unchanged. This approach is a pragmatic means to determine whether the size of a tumor has changed over the course of time.