RESTING-STATE FUNCTIONAL MRI DEMONSTRATES DAMAGE TO FUNCTIONAL CONNECTIVITY IN MENINGIOMA PATIENTS WITH PERIFOCAL EDEMA

Abstract BACKGROUND Meningiomas are common intracranial tumors which usually carry a benign prognosis. Some meningiomas cause perifocal edema which might indicate that this subset could interfere with normal brain function. Resting-state functional MRI (rsfMRI) can be used to assess whole brain functional connectivity (fc) which can be used as a marker for disease severity in patients with intracranial tumors, as was recently shown by our group in a cohort of glioma patients. In this study, we investigated whether the presence of perifocal edema in preoperative patients with meningioma leads to fc. METHODS Patients with suspected meningioma were prospectively included and functional resting state MRI scans were obtained. The resulting data was processed according to our recently published method and abnormality of fc was quantified for each individual patient. Abnormality of fc was then correlated with tumor and edema volume as well as WHO grade. RESULTS 26 patients (23 WHO grade I, 3 WHO grade II) were included. 13 patients had perifocal edema. There was a highly significant correlation between edema volume and higher abnormality of fc both in the lesional and the contra-lesional hemisphere (r=0.51, p=0.008 and r=0.61, p=0.001). Patients with no perifocal edema showed only very low abnormality of fc. Tumor volume was not correlated with abnormal fc in both the lesional and the contralesional hemispheres (r=0.23, p=0.27 and r=0.28, p=0.17). There was also no significant correlation between WHO grade and abnormality of fc. CONCLUSION RsfMRI showed significant abnormal fc in meningioma patients with perifocal edema in contrast to patients without edema, independent of tumor volume. This demonstrates that the presence of edema but not the tumor volume is relevant for disturbances of fc.