LAUSR

OBJECTIVES Meningioma is one of the most common primary intracranial tumors. Diagnosis by imaging is not difficult. However evaluation of tumor consistency is an important factor affecting the surgical outcomes. The purpose of our study is to discover the relationship of different findings on pre-operative MRI, with a focus on detailed architectures, and different degrees of intra-operative stiffness of meningioma. Consistency of meningioma is also analyzed in compression to semi-quantitative pathological grading of fibrosis. PATIENTS AND METHODS Sixty patients who underwent pre-operative MRI and primary surgery at our hospital were included in prospective fashion. Pre-operative MRI parameters, including general data and detailed internal architectures, were recorded. Intra-operative grading of tumor consistency was performed by the neurosurgeon. Pathological report according to WHO 2007 was performed with additional semi-quantitative grading of fibrosis. This study is focused on correlation of operative grade and MRI findings. RESULTS Meningioma with hard consistency shows significant correlation with several features including en plaque appearance (p = 0.0427), higher ADC value (p = 0.0046) and ratio (p = 0.0016), absent of prominent enhanced rim (p = 0.0306), absent of enostotic spur (p = 0.0040) and absent of vascular core (p = 0.0133) in univariate analysis but no significant correlation is found in multivariate analysis in all except ADC ratio. Higher ADC ratio increase relative risk of hard consistency of meningioma by a factor of 41.22 (ORs = 41.22; 95%CI = 1.19-1426.24, P = 0.04). Good to very good inter-rater agreements are found. No significant correlation between tumor consistency and WHO grading was shown (p = 0.606). However, near significant p-value (p = 0.055) is found with increase degree of fibrosis in pathology as increase degree of tumor consistency. CONCLUSION We found that en plaque appearance, higher ADC value and ADC ratio, absent of prominent capsular enhancement and absent of vascular core were suggestive of hard consistency in univariate analysis but not independent factors. Additionally, semi-quantitative pathological grading of fibrosis showed near significant correlation with tumor consistent.