Differentiating between spinal schwannomas and meningiomas using MRI: A focus on cystic change

OBJECTIVES: To retrospectively determine the diagnostic ability of MRI in differentiating between intradural extramedullary spinal schwannomas and meningiomas. METHODS: A total of 199 patients with spinal intradural extramedullary tumors who underwent preoperative contrast-enhanced MRI between January 2012 and December 2018 were included in this study. Two radiologists independently analyzed the presence of cystic change, dural tail sign, and neural foraminal extension. Clinical and MRI features between the two groups were compared by univariable and multivariable analyses using logistic regression. Interobserver agreements were calculated using kappa statistics. RESULTS: Patients with schwannoma showed significantly higher frequency of cystic change (96% vs 24%, P < 0.001), neural foraminal extension (29% vs 3%, P = 0.001), and lumbar location (41% vs 5%, P = 0.008). Patients with meningioma showed significantly higher frequency of dural tail sign (64% vs 1%, P < 0.001), thoracic location (75% vs 31%, P = 0.007), older age (59.7 years vs 47.6 years, P < 0.001), higher female predominance (83% vs 50%, P < 0.001), and smaller size (19.8 cm vs 28.8 cm, P < 0.001). Multivariable analysis showed that cystic change (P < 0.001; odds ratio [OR], 0.02), dural tail sign (P < 0.001; OR, 36.23), age (P = 0.032; OR, 1.06), and lumbar location (P = 0.006; OR, 0.02) were independent factors. Interobserver agreements were almost perfect for all analyses. CONCLUSIONS: MRI features were useful in differentiating between intradural extramedullary schwannomas from meningiomas. The presence of cystic change and dural tail sign were independently significant discriminators.