Dynamic Measurement Of Cervical Spinal Canal And Cervical Spinal Cord Volume

Objectives:First,to measure the cervical spinal canal and cervical spinal cord volume of healthy people and cadavers through pouring and on MRI,and also to evaluate the dynamic changes of the cervical spinal canal and cervical spinal cord volume with the angle change of the cervical vertebral.Second,to introduce a measurement method of the cervical spinal canal and cervical spinal cord volume.Methods:First,six adult specimen of cadavers(C3-C7) are used for this test.Before test,they are inspected and confirmed no fracture and obviously degeneration and deformity. During MRI,the study subjects are in the supine position,and the speciman is first fixed in the central position.The T1-weighted sagittal sectional images(1.0-mm continuous slices) are obtained using a 1.5T MRI system with three-dimensional spoiled gradient-recalled sequence.The sagittal sectional area of the spinal cord is measured by using a cursor to trace the outline of the spinal cord on each slice,and the spinal cord volume is calculated by integrating the sagittal sectional area.Then the speciman is scanned in the flexion and extension positions.Second,twenty healthy people are chosen to experiment,and four individuals of all are excluded because of degeneration,deformity or in fear of the scan.The remaining 16 individuals are conducted MRI scan.Last,we analysis the conclusions and evaluate their dynamic changes.Results:1.By results of the two mathematical correlation analysis,we find the test shows that determination coefficient(R~2) is 0.915 and the gradient is 0.862. 2.The volume of the spinal canal shows a significant linear correlation with the total angle of flexion or extension(r = 0.972,P＜0.05).on average,a change in flexion-extension angle of 20°is required to produce a volume change of 1ml.3.The volume of the cervical spinal canal shows a same change trend whether specimen of cadavers or healthy people,that is,the volume is larger in flexion position than in the central position,and the volume is larger in central position than in the extension position,and also their volumes have a significant difference(P＜0.05).4.The volume of the cervical spinal cord shows a same change trend whether specimen of cadavers or healthy people,that is,the volume in flexion position is same as that in the central position,and the volume in central position is same as that in the extension position,and also their volumes have no significant difference(P＞0.05).Conclusions:1.The volume of the cervical spinal canal decreases monotonically with increasing extension angle,in a linear fashion,because of decrease in length and width of the canal,and also increases monotonically with increasing flexion angle.2.The volume of the spinal cord is always the same size with changing the angle of cervical vertebral,but the shape and location of the spinal cord is changing in the cervical spinal canal.3.MRI can be used to measure the volume of no apparent degeneration cervical spinal canal and the spinal cord,and we consider that measurement of the cervical spinal canal volume on MRI has a high reliability.