Multimodality MRI Study Of Brain Structure And Function In Patients With Cervical Spondylotic Myelopathy

Object:Cervical Spondylotic Myelopathy(CSM)is the most common chronic myelopathy which is caused by degeneration of intervertebral disk,limb dysfunction,sensory loss,and pain.CSM refers to a special spinal cord injury(SCI).Traditional therapy focuses on spinal column and cord abnormalities since it is associated with the local compressive impairment.However,spinal cord compressing impacts the permanent cerebral structure changes and functional reorganization with long-term loss of input sensory and output motor stimulation.Previous studies have demonstrated that compensatory cerebral functional adaptation changes before surgery in patients with Cervical Spondylosis Myelopathy(CSM)by using task-fMRI,especially in sensorimotor cortices.However,the sensorimotor cortices structural changes in the human brain following CSM still remain poorly understood.The purpose of this study was to assess the volumetric changes of sensorimotor cortices using morphological MRI and volumetric changes correlated with clinical scales.Methods:This research were divided into three parts:1.the changes of brain structure in patients with cervical spondylotic myelopathy.The study participants included thirty patients with CSM and matched twenty-five healthy controls.Patients underwent brain morphological MRI before surgery.Segment brain into white matter and grey matter using DARTEL algorithm by VBM.Use BA1,BA2,BA3a,BA3b,BA4a,BA4p,BA5,BA6,thalamus and cerebellum as ROI to compare the volume of grey matter between CSM patients and healthy controls.Then check the correlation between atrophy volume and JOA scores,including upper motor score,lower motor score,sensory score and sphincter dysfunction score.2.The changes of brain function in patients with cervical spondylotic myelopathy.Thirty CSM patients who need surgery therapy and twenty-five matched healthy controls underwent resting state fMRI(rs-fMRI)scan.SPM12 and DPARSF software were used to process the functional images,and the amplitude of low frequency fluctuations(ALFF)method were used to analysis brain sensorimotor system functional changes.Furthermore,analysis the brain network level changes by using the functional connectivity(FC)method.The value of ALFF and FC were extracted by REST software and correlated to the JOA scores and subgroup scores using Pearson correlation.The profiles of photography theory were obtained by Gretna toolbox and compared between CSM patients and healthy controls.3.The change of brain structural and functional and recover mechanism after recompression surgery.The fifteen CSM patients underwent fMRI,structure MRI and DTI scan before surgery and 6 months after surgery.The structure MRI images were processed by Freesurfer longitudinal method.The ALFF and FC strength were compared between preoperative patients group and postoperative patients group.The profiles of photography theory were obtained by Gretna toolbox and compared between two group.The FSL and TBSS method were used to process the DTI images.The value of FA,MD,AD and RD were compare between preoperative group and postoperative group,besides preoperative group and healthy controls.Results1.the changes of brain sensorimotor cortical in patients with cervical spondylotic myelopathy.Compared to healthy controls,patients with CSM showed significant atrophy at left BA1,left BA2,left BA3a,right BA3a,left BA3b,left BA4a,right BA4p,left BA5,right BA6,left and right thalamus.In addition,gray matter volume in the S1,M1 and thalamus were positive linear correlated with the motor score of Japanese Orthopedic Association(JOA)score in patients with CSM patients.The change of SMA positive linear correlated with the sphincter score of JOA score in CSM patients.2.The changes of brain function in patients with cervical spondylotic myelopathy.Left BA1,right BA6 and left cerebellum of CSM patients showed significant increased ALFF than healthy controls.There was no significant correlation between increased ALFF value and clinical score.The CSM patients showed significant FC between right BA6 and left thalamus,left cerebellum.Furthermore,there was significant correlation between BA6 connected to left thalamus and upper motor score(p=0.029,r=0.04).Compared to healthy controls,the CSM patients had higher degree centrality at left parietal sensorimotor and left occipital sensorimotor,higher nodal local efficiency at left medial and inferior cerebellum,lower degree centrality at left thalamus,right medial cerebellum,right aPFC,right d1PFC and post-cigulate.3.the changes of brain sensorimotor cortical in patients with cervical spondylotic myelopathy.There was no significant structural thickness difference between preoperative patients and postoperative.Postoperative patients showed significant decreased ALFF at left cerebellum than preoperative patients.Postoperative patients and healthy controls showed significant decreased FC between left thalamus and right sensorimotor cortical than preoperative patients.Compared to preoperative,the postoperative patients had higher degree centrality at right parietal sensorimotor and left cerebellum,lower degree centrality at right thalamus,right aPFC and v1PFC,lower local shortpath at left cerebellum and lower nodal local efficiency at post cingulate.The preoperative patients showed significant increased FA value at left superior longitudinal fasciculus temporal part,and decreased AD at right superior longitudinal fasciculus than healthy controls.The postoperative patients showed significant increased FA both side corticospinal,decreased MD,AD,RD at cingulum and right anterior thalamic radiation.Conclusions:1.Sensorimotor cortical include left BA 1,left BA2,left B A3 a,right B A3 a,left BA3b,left BA4a,right BA4p,left BA5,right BA6,left and right thalamus atrophy in CSM patients.And sensorimotor atrophic volume had correlated with clinical scale.2.In CSM patients showed significant increased ALFF at left BA1,right BA6 and left cerebellum to compensate sensorimotor cortical atrophy.3.BA6 of CSM patients had higher functional connectivity to left thalamus and left cerebellum than health controls.Furthermore,the FC strength of BA6 to left thalamus had positive correlation with upper motor score.4.In whole brain network level,the left sensorimotor network had decreased degree centrality in CSM patients.Other area showed compensated increased degree centrality.5.Postoperative patients using left cerebellum as seed showed decread FC strength than preoperative patients.6.CSM patients compensated left cerebellum increase ALFF declined as normal after recompression surgery.7.Preoperative patients showed decreased FA in contralateral superior longitudinal fasciculus than healthy control,ipsilateral superior longitudinal fasciculus compensated increased.Postoperative patients showed decreased FA in both side corticospinal and value of MD,AD,RD at cingulum and anterior thalamic redaction increased than preoperative patients.8.The mechanism of motor function recovery in patients with cervical spondylotic myelopathy is atrophy of the cortex in the motor sensory region after spinal cord compression.Activity and functional connectivity in the relevant brain regions increase to compensate for the loss of signal.After signal recovery after decompression,the compensatory response will gradually decrease with the recovery of function.At the same time,the activity efficiency and degree centrality of sensorimotor cortices and cerebellar on the left side increase,and assist in the recovery of motor sensory function.