title: [Intraoperative high-field magnetic resonance imaging combined with functional neuronavigation in resection of low-grade temporal lobe tumors involving optic radiation].
abstract: OBJECTIVE
  To investigate the clinical value of high-field-strength intraoperative magnetic resonance imaging (iMRI) combined with optic radiation neuro-navigation for the resection of temporal lobe low-grade gliomas.
  
  
  METHODS
  From April 2009 to September 2013, 65 patients with temporal lobe low-grade gliomas (WHO grade II) involving optic radiation were operated with iMRI and functional neuro-navigation. Diffusion tensor imaging (DTI) based fiber tracking was used to delineate optic radiation. The reconstructed optic radiations were integrated into a navigation system, in order to achieve intraoperative microscopic-based functional neuro-navigation. iMRI was used to update the images for both optic radiations and residual tumors. Volumetric analyses were performed using 3D Slicer for pre- and intra-operative tumor volumes in all cases. All patients were evaluated for visual field deficits preoperatively and postoperatively. The Student t test was used to evaluate the average rate of extent of resection between groups. Spearman rank correlation analysis was used to assess correlations between predictors and epilepsy prognosis.
  
  
  RESULTS
  Preoperative tumor volumes were (78±40) cm3. In 29 cases, iMRI scan detected residual tumor that could be further resected, and extent of resection were increased from 76.2% to 92.7% (t=7.314, P<0.01). In 19 cases (29.2%), gross total resection was accomplished, and iMRI contributed directly to 8 of these cases. Postsurgical follow-up period varied from 13 months to 59 months, mean (33±13) months. Tumor progression were observed in 3 patients, newly developed or deteriorated visual field defects occurred in 4 patients (6.2%). For patients with pre-operative seizures, Engel Class I were achieved for 89.7% of them. Spearman rank correlation analysis revealed that seizure outcome (Engel Class) was related to increased excision of ratio (r=-0.452, P=0.004, 95% CI: -0.636--0.261) and larger tumors (r=0.391, P=0.014, 95% CI: 0.178-0.484).
  
  
  CONCLUSIONS
  With iMRI and functional neuro-navigation, the optic radiation can be accurately located, while extent of resection can be evaluated intra-operatively. This technique is safe and helpful for preservation of visual field for the resection of temporal lobe low-grade gliomas involving optic radiation.
authors.affiliation: Department of Neurosurgery, People's Liberation Army General Hospital, Beijing 100853, China.
authors.forename: Shaocong
authors.initials: S
authors.lastname: Bai
authors.affiliation: Department of Neurosurgery, People's Liberation Army General Hospital, Beijing 100853, China.
authors.forename: Xiaolei
authors.initials: X
authors.lastname: Chen
authors.affiliation: Department of Neurosurgery, People's Liberation Army General Hospital, Beijing 100853, China.
authors.forename: Jiefeng
authors.initials: J
authors.lastname: Geng
authors.affiliation: Department of Neurosurgery, People's Liberation Army General Hospital, Beijing 100853, China.
authors.forename: Dongdong
authors.initials: D
authors.lastname: Wu
authors.affiliation: Department of Neurosurgery, People's Liberation Army General Hospital, Beijing 100853, China.
authors.forename: Xinguang
authors.initials: X
authors.lastname: Yu
authors.affiliation: Department of Neurosurgery, People's Liberation Army General Hospital, Beijing 100853, China; Email: xubn010@163.com.
authors.forename: Bainan
authors.initials: B
authors.lastname: Xu
mesh_terms: D001932:Brain Neoplasms / Q000473:pathology / Q000601:surgery*; D005910:Glioma / Q000473:pathology / Q000601:surgery*; D006801:Humans; D008279:Magnetic Resonance Imaging; D038361:Neuronavigation; D013702:Temporal Lobe / Q000601:surgery*