Understanding network reorganization after glioma regrowth: comparing connectivity measures from functional magnetic resonance imaging to direct cortical stimulation

Task specific networks in the human brain can be complex and variable inter-individually. New tools such as connectivity analysis were prompt as useful for network evaluation in patients without structural brain disease. However, these tools lack clinical understanding and correlation. We aimed to analyze task specific connectivity measures in pre-surgical planning in patients with low grade gliomas and evaluate their changes after tumor regrowth. We recruited three patients submitted to awake craniotomy resection with direct cortical stimulation (DCS) guided by a navigational system. They performed functional magnetic resonance (fMRI) in pre-surgical planning and after tumor regrowth. Connectivity measures were extracted from motor and language tasks done during fMRI acquisition. We correlated connectivity with clinical evaluation, DCS finding's and compared with fMRI after tumor regrowth. We found a reduced participation coefficient in precentral gyri in a patient with reduced hand strength. Regarding language, homolateral and contralateral hemisphere reorganization was observed with higher participation coefficient or betweenness centrality. Functional connectivity measures provided insight about individual brain region's role in motor and language function in pre-surgical planning. Further understanding of brain reorganization was provided by connectivity analysis after tumor regrowth.