Objective: To assess the value of integrating blood oxygen level dependent (BOLD) functional magnetic resonance imaging (fMRI) in neuronavigation surgery of brain tumors involving motor cortex.
Methods: A total of 58 patients with brain tumors in or directly adjacent to the motor cortex, with 18 lesions located in primary motor area, 18 lesions located in premotor area, 11 lesions located in primary motor sensory area, 9 lesions located in primary sensory area, and 2 lesions located in supplementary motor area respectively, were randomly divided into 2 groups: trial group including 30 cases undergoing BOLD navigation and control group with 28 cases undergoing routine navigation. A prospective random and matched controlled study was carried out to compare the clinical outcome between the two groups. For the patients in the trial group, the motor tasks consisted of simple flexion-extension finger movements and finger-to-thumb touching in a repeating, pre-planned sequence of either hand. A standard 1.5 T MR system had been utilized to localize the cortical motor hand area, using the BOLD contrast technique. The BOLD images were integrated with the routine navigational MR images (T1-weighted three-dimensional fast spoiled gradient recalled sequence), and then co-registered to the neuronavigation system. For the patients in the control group, the navigational MR imaging examinations were carried out only.
Results: The statistics analysis confirmed a good balance of main variations between the trial and control groups. The percentage of completely resection of tumors was 86.7% in trial group and 60.7% in control group (P < 0.05). The postoperative contralateral extremities muscle strength were 4.3 +/- 1.1 degree for trial group and 2.5 +/- 1.9 degree for the control group (P < 0.01). The motor functional deficit was observed in 23.3% of the cases of trial group and 71.4% of the cases in trial group (P < 0.05). The mean Karnofsky prognosis scale of the trial group was 88 +/- 27, significantly higher than that of the control group (65 +/- 32, P < 0.01).
Conclusion: BOLD functional MR imaging is of great value in surgical planning and intraoperative functional brain mapping of motor cortex individually. To integrate BOLD data with the routine navigational MR images can supply more precise and real-time information about the relationship between lesions and neighboring cortical motor area. It should be used in neuronavigation surgery to increase the ratio of total resection of brain tumors and decrease the risk of postoperative hemiplegia.