MRI evaluation of neurofibromatosis 2 patients: a standardized approach for accuracy in interpretation
To determine the level of agreement between local radiologists' and an experienced neuroradiologist's measurements of vestibular schwannomas. Prospective study with uniform magnetic resonance acquisition protocol parameters and reporting instructions across 30 magnetic resonance imaging facilities worldwide. Multicenter natural history study of neurofibromatosis Type 2. One hundred fifteen magnetic resonance imaging examinations of 57 neurofibromatosis Type 2 patients older than 5 years of age. Thin-slice, postcontrast cranial magnetic resonance imaging. Spearman's rho interobserver association coefficient of vestibular schwannoma linear measurements. The local and experienced radiologist measurements and identification of tumors agreement was fair (kappa = 0.77). Discordant interpretations were adjudicated by another experienced neuroradiologist. The least interobserver variability was found in measurements of thin-slice postcontrast magnetic resonance imaging scans obtained at neurofibromatosis Type 2 centers in patients without previous operations and moderately sized tumors. If the schwannoma was difficult to assess, because of magnetic resonance imaging acquisition protocol, postoperative changes, or tumors smaller than 5 mm in greatest diameter, the neuroradiologist provided a more thorough assessment. The authors suggest uniform reporting criteria for vestibular schwannoma assessments to ensure clinically relevant information is communicated regarding vestibular schwannoma size.