The Multimodal MRI Study Of Visualization Of The Subthalamic Nucleus And Effect Of Active Contact Location On Clinical Efficacy Of Deep Brain Stimulation

Background:Subthalamic nucleus stimulation has been widely used in the treatment of Parkinson’s disease and dystonia and other diseases,but for preoperative subthalamic nucleus localizatino,intraoperative intracranial gas accumulation affects the accurate implantation of the electrode and the effect of postoperative electrode active contact position on clinical efficacy of deep brain stimulation.So it is necessary to further study and discuss issues above.Objectives:1.To assess the visualization of subthalamic nuclei by different magnetic resonance sequences under 3T preoperative MRI;2.Study the relationship between intracranial gas and postoperative short-term and long-term electrode displacement,and propose a solution;3.Analysis of the effect of active contact location on clinical efficacy of deep brain stimulation for dystonia and Parkinson’s disease.Methods:1.To compare the effect of different preoperative sequences(T2 TSE,T2-FLAIR,SWI and QSM)on subthalamic nuclei;2.Using postoperative thin-section CT analysis of the relationship between intracranial gas volume and brain tissue displacement,preoperative multi-modal NMR and postoperative thin-section CT fusion analysis of intracranial gas after surgery for short-term and long-term electrode displacement.Then we studied a method of reducing cerebrospinal fluid loss in DBS.3.Three-dimensional reconstruction of the electrode location with the preoperative multimodal MRI and postoperative thin-section CT,and then calculating volume of tissue activation(VTA)according to the stimulation parameters.The next step is to study the effect of volume of tissue activation within subthalamic nucleus in the treatment of dystonia and Parkinson’s disease.Results:1.The qualitative score of QSM was significantly higher than that of SWI,T2-FLAIR and T2 TSE.The consistency Kappa test was 0.892,p<0.01.The STN to substantia nigra was calculated quantitatively(T2 TSECNR 0.95 ± 0.68,T2-FLAIRCNR= 1.36± 0.85,SWICNR = 3.12 ± 2.44,QSMCNR = 5.04 ± 3.70)showed that the contrast-to-noise ratio of QSM was the highest,with p<0.01 compared to the rest of the sequences.2.Correlation analysis between the left and right side frontal lobe displacement by thin-section CT was performed,the correlation coefficients r2 were 0.7008 and 0.6739,respectively,p<0.01.The intracranial gas volume(2784 ± 675.6 mm3 on the left and 2789 ± 673,8 mm3 on the right)were significantly less than those of the traditional method(left side 9833 ± 2184 mm3,right side 9319 ± 1981 mm3)Side 4.648 ± 0.6027 mm)was significantly lower than the traditional method(left 9.502 ±0.7767 mm,right 8.696 ± 0.7259 mm),p<0.01.3.Fourteen patients improved from 22.1±11.6 preoperative to 6.3±5.9 at latest follow-up(14.5±3.7 months),with a mean improvement of 70.9%(p =0.001).One patient was lost follow up.According to the preoperative and postoperative images of 15 patients with Meige,the three-dimensional reconstruction of DBS postoperative electrodes was realized by using MATLAB and Lead DBS software.Localization of active electrode contacts in Montreal Neurological Institute(MNI)space were:x=-12.5±1.2 mm,y=-13.2±1.7 mm,z=-5.5±2.5 mm for the left side;x= 11.8±1.6 mm,y=-2.0±1.8 mm,z=-3.0±2.2 mm for the right side.The contacts used for stimulation were mainly clustered in the dorsal region of the STN.Within that region,we found positive correlation between the volume of tissue activated within STN and BFMDRS improvement,R=0.604,p=0.022.The coordinates(mean ± standard deviation)of left electrode activated contacts after STN DBS in 54 PD patients were x =-12.7 ± 1.2 mm,y =-13.2 ±1.7 mm,z =-6.4±1.6 mm;the coordinates of the activated electrode contact on the right side(mean ± standard deviation):x =-13.1±1.3 mm,y =-12.5±2.0 mm,z =-6.3 ± 1.8 mm.There was a positive correlation between VTA and BFMDRS score in STN,the correlation coefficient R = 0.38,p<0.005.Conclusions:1.QSM is the best sequence currently showing subthalamic nuclei.2.The new method is better than traditional methods to reduce intracranial gas,so as the electrode displacement can be reduced.3.These findings suggest the active contacts used for stimulation on the dorsal STN may provide good clinical effect in dystonia,which was similar in patients with Parkinson’s disease.