Introduction: This study was undertaken to correlate MRI signals with operative consistency, vascularity, surgical plane and histopathology of meningiomas.
Methods: Patients with meningioma underwent T1, T2, FLAIR and contrast MRI, and those planned for excision were enrolled for the study. Clinico-demographic details, signal intensity of tumor in various sequences, and contrast enhancement were prospectively noted, and studied in relation to intra-operative tumor consistency, vascularity, dissection plane, Simpson’s grade, and histopathology. SPSS21 was used for univariate and multivariate analysis.
Results: Of the total 70 patients (44 females, 26 males), 18 had skull base, 15 had convexity, 10 had parasagittal, 11 had falcine, and 7 had tentorial meningiomas. Majority (67) had tumors which were hypo to isointense in T1. While 14 had hypointense signal in T2, only 8 were hypointense in FLAIR. 21 had inhomogeneous enhancement. 28 had marked tumor interface in MRI, while 33 and 9 had regular and irregular border respectively. 19 had no edema, while 33 and 18 had focal and lobar edema respectively. Inhomogeneous enhancement (p=0.01) and FLAIR hypointensity (p=0.03) had significant association with operative tumor hardness. FLAIR hypointensity (p=0.01) had significant association with low vascularity. Skull base location (p=0.04), FLAIR hypointensity (p=0.02), irregular border (p=0.01), and recurrence (p=0.01) had significant association with subpial or mixed plane of cleavage. Only skull base location (p=0.01) had significant impact on extent of excision. T2 hypointensity (p=0.001) and FLAIR hypointensity (p=0.01) had significant association with Fibroblastic or Psammomatous meningioma. In multivariate analysis, FLAIR hypointensity (p=0.02) and skullbase location (p=0.04) had significant independent association with suboptimal surgical plane, while skull base location (p=0.01) had significant association with extent of excision. Among MRI sequences, FLAIR hypointensity had the highest specificity of 94% to predict suboptimal surgical plane.
Conclusions: FLAIR hypointensity of meningioma in MRI appears to have significant independent association with suboptimal surgical plane with high specificity.
Patient Care: Prediction of operative findings in MRI would make the surgeon anticipate intra-op difficulties and well prepared for better outcome.
Learning Objectives: By the conclusion of this session, participants should be able to: 1) Describe the importance of MRI sequences in preoperative planning of meningiomas, 2) Identify tumors which are likely to pose operative challenges in the form of hard consistency, high vascularity, and suboptimal surgical plane, influencing extent of excision, 3)Predict using MRI, the likely histopathology of meningiomas.