The Application Of BOLD-fMRI And DTI Integrated With Intraoperative MRI And Neuronavigation On Brain Tumors Involved The Primary Motor Cortex

Objective:The integration of blood oxygen level dependent functional magnetic resonance imaging (BOLD-fMRI) and diffusion tensor imaging (DTI) with intraoperative magnetic resonance imaging (iMRI) and neuronavigation is a new technique for surgery involved the primary motor cortex. However, the clinical practical value remains to be proved. In this study, we investigated the feasibility of BOLD-fMRI and DTI in clinical application and the influencing factors on BOLD-fMRI and DTI in brain tumors involved the primary motor cortex. The effect of BOLD-fMRI and DTI integrated with iMRI and neuronavigation on eloquent cortex protection, tumor resection rate and postoperative neurological deficit were evaluated.METHODS:From February 2009 to November 2009, Surgeries were performed in 72 patients with brain tumors involved the primary motor cortex with BOLD-fMRI and DTI integrated with iMRI and neuronavigation in the Department of Neurosurgery of Chinese PLA General Hospital. Prospective studies were undertaken to observe the feasibility in BOLD-fMRI and DTI signal acquisition. Diffusion tensor tractography (DTT) was constructed by five individual investigators and the same investigator for five times. BOLD signal was studied in cases of different histopathologic tumors, different distance from tumor margin to activated eloquent cortex and different peritumor edema. The influence of patient age and tumor volume on the BOLD signal was analyzed using linear regression model. The patients were divided into four groups according to the distance between tumor margin and activated eloquent area. The incidence of postoperative motor deficits in four groups was studied using fisher exact test. The effects of various histopathology of the tumors, various distance from tumor margin to pyramidal tract and various degree of the peritumor edema on pyramidal tract volume were studied. The patients were divided into two groups according to the distance between tumor margin and pyramidal tract. The incidence of postoperative motor deficits in two groups was studied using fisher exact test. The effects of iMRI and neuronavigation on total resection rate were analyzed using Mann-Whitny U test.RESULTS:Among 72 patients, BOLD-fMRI signal was obtained well in 59 patients, however BOLD-fMRI signals wasn't obtained well until paresis fingers or toes were moved passively in the other 13 patients (18.1%) who had decreased muscle strength and increased muscle tonus. DTI was collected well in all patients. The reproducibility of pyramidal tract constructed by five individual investigators and the same investigator five times can be seen. BOLD signal decreased obviously in the glioblastoma and metastatic tumor groups. A significant BOLD signal decreasing in the group with obvious peritumor edema and the group of the distance less than 10mm between tumor margin and activated eloquent cortex was observed. Patient age was negatively correlated with BOLD signal in the meningioma group. The incidence of postoperative motor deficits increased greatly in the groups of the distance between tumor margin and activated eloquent cortex less than 10mm. Pyramidal tract volume decreased obviously in every group. The incidence of postoperative motor deficits increased greatly in the group of the distance between tumor margin and pyramidal tract less than 5mm. The application of Intraoperative MRI and neuronavigation could promote total resection rate from 44.2% to 86% in intra-axial tumors. The residual tumor volume was reduced greatly between the first and the last intraoperative MRI scan.CONCLUSION:BOLD-fMRI and DTI can be successfully applied to the neurosurgical cases. BOLD signal decreased obviously in the groups of glioblastoma and metastatic tumor, the groups of obvious peritumor edema and the group of the distance less than 10mm between tumor margin and activated eloquent cortex. The incidence of postoperative motor deficits increased greatly in the groups of the distance less than 10mm between tumor margin and activated eloquent cortex and the distance less than 5mm between tumor margin and pyramidal tract. The integration of BOLD-fMRI and DTI with iMRI and neuronavigation could help neurosurgeons resect the tumors maximally and reduce the occurrence of neurological deficits by the surgery.