The Application Study Of3.0T MR Diffusion Tensor Imaging In Cervical Spondylotic Myelopathy

[Objectives]1. To analyze the characteristic of diffusion tensor imaging (DTI) parameters in allthe intervertebral space levels of the cervical spinal cord (CSC) and to study theimpact of age on these parameters.2. To Study the diagnosis and prognosis value of apparent diffusion coefficient (ADC)ratio and fractional anisotropy (FA) ratio of DTI in different degrees of cervicalspondylotic myelopathy (CSM)3. To Study the diagnosis and prognosis value of diffusion tensor tractography (DTT)of DTI in CSM[Materials and Methods]1. DTI parameters were calculated for gray matter (GM) and white matter (WM)funiculi in all the intervertebral space levels of the CSC (C1/2-C6/7) in36healthysubjects (20-77years old). Age-related changes of DTI parameters were analyzed forthe gray matter (GM) and white matter (WM) funiculi.2. Ninety three CSM patients, were enrolled from2011September to2013March inour department，thirty six healthy volunteers were enrolled as control from our facultyof our hospital. All the subjects received MRI examination after informed consent wasobtained. For the CSM patients, the ADC and FA values measured in mostcompression level and C1/2level, and the ADC and FA ratios were calculated bydividing the DTI parameters of compression levels into the parameters of C1/2level.For the volunteers, the ADC and FA values measured in C1/2, C3/4, C4/5, C5/6, andC6/7level, and the ADC and FA ratios were calculated by dividing the DTIparameters of C3/4, C4/5, C5/6, C6/7levels into the parameters of C1/2level.Function of the CSM patients was evaluated by JOA scores before and after theoperation, and the JOA recovery rate was calculated after the end follow-up. Patientswere divided into four degrees according to the preoperative JOA scores, mild group (13-16score), moderate group (9-12score), and severe group (0-8score). All thepatients were divided into four degrees according to the JOA recovery rate,Ⅰgrade(0-34%),Ⅱgrade (35%-67%), Ⅲ grade (68%-100%). Difference of DTI ratios werecompared between different JOA score groups and JOA recovery rate groups.3. All the patients enrolled in part2received MRI and DTI examinated. The patientswere divided into three degrees according to the MRI signal changes, A group(compression of spinal cord but no abnormal signal changes on sagittal T1WI andT2WI), B group (severe compression of spinal cord and high signal on sagittalT2WI),and C group (serious compression of spinal cord and low signal on sagittalT1WI). All the patients were divided into three degrees according to the DTT changes,A group (compression of spinal cord but normal fiber bundles), B group (severecompression of spinal cord and disorder of fiber bundles), and C group (seriouscompression of spinal cord and definition interrupt of fiber bundle). Difference of thediagnosis and prognosis value was compared between MRI and DTT classification.[Results]1. Fractional anisotropy (FA), apparent diffusion coefficient (ADC) showedsignificant differences between GM and individual WM funiculis, between differentsegments, and between different aging groups. Significant age-related changes wereobserved in FA and ADC from gray matter (GM) and white matter (WM) funiculi.The correlation of FA and age was greater.2. According to the JOA score grade, difference was observed only in ADC ratios ofventral funiculus (VF) in white matter (WM), FA ratios of VF and gray matter (GM)between moderate group of CSM patients and control group. Between severe andcontrol group, difference was observed in ADC ratios and FA ratios of VF, lateralfuniculi (LF), and GM. Between serious and control group, difference was observedin ADC ratios and FA ratios of all the WM funiculi and GM. According to the JOArecovery groups, difference was observed in ADC ratios of VF, LF, DF, and GMbetween all the CSM groups and control group. Being Different with ADC ratios, difference was observed in FA ratios of WM funiculus and GM betweenⅠgroup andcontrol group, in FA ratios of VF, LF, and GM betweenⅡgroup and control group, inFA ratios of VF and GM between Ⅲ group and control group.3. There was a correlation between MRI classification and the JOA score, but nocorrelation between MRI classification and JOA recovery rate. There was correlationbetween DTT classification and the JOA score, DTT classification and JOA recoveryrate. Compared with the MRI, DTT classification and JOA score correlated greater.[Conclusions]1. This study focus on the DTI data of GM and WM funiculi in all the intervertebrallevels of the cervical spinal cord. While DTI parameters may be used to define cordpathology, variations in parameters due to age and segment need to be accounted forbefore making definitive conclusions.2. The diagnosis and prognosis values of ADC ratio, FA ratio and DTT for CSM arehigher than conventional MRI. DTI can be used for quantified assessment.3. The diagnosis and prognosis values of DTT classification were higher than MRIclassification.