Study On Multi-parameter MR Imaging And Measurement Method Of Spinal Cord Gray Matter

Purpose: To evaluate the application value of T2 WI,PDWI and multiple-echo data image combination(MEDIC)in spinal cord gray matter imaging.To investigate the consistency of quantitative parameter measurement of spinal cord and gray matter.Material and Methods: We acquired sagittal 3D T2WI/SPACE images of cervical cord and thoracic cord,axial T2 WI,PDWI,MEDIC images of cervical cord on 40 healthy subjects at 3T magnetic resonance machine.The T2 WI,PDWI and MEDIC images of cervical spinal cord gray matter were scored by two radiologists.ICC were used to analyze the scores of cervical spinal cord transection displayed by two radiologists with three sequences,and Rank sum test were used to analyze whether there were any difference in cervical spinal cord gray matter displayed by different sequences.Transverse spinal cord images were reconstructed on 3D T2 WI SPACE images by two experienced radiologists(P1 and P2),and then,the cross-sectional area,left-right diameter and anterior-posterior diameter of the spinal cord were manually delineated.Based on MEDIC sequences,the spinal cord gray matter area corresponding to C2-3,C3-4,C4-5 and C5-6 intervertebral discs were manually delineated.One month later,one of radiologist(P1)measured all data again.At the same time,the MR images of 40 healthy volunteers were automatically processed by the Spinal Cord Toolbox(SCT),the cross-sectional area and gray matter area of the spinal cord were calculated.Intra-class correlation coefficients were used to analyze the consistence of gray matter parameters in different measure time and in different observers.Results:(1)The consistency of the scores of spinal cord gray matter displayed by two radiologists(P1 and P2)were ICC=0.897.(2)The score of T2 WI,PDWI and MEDIC in gray matter display were 0,44 and 71,MEDIC got the highest score,and the difference were statistically significant(P<0.05).(3)The coefficient of measurement results between two radiologists(P1,P2),T2/SPACE: the intra-class correlation coefficient of cross sectional area of spinal cord,left-right diameter,anterior-posterior diameter were0.967,0.957 and 0.777 respectively.MEDIC: the ICC of cervical spinal cord gray matter were 0.565.(4)The coefficient of measurement results in the same radiologist measured in different time,T2/SPACE: the ICC of cross-sectional area,right-left diameter,anterior-posterior diameter were 0.979,0.960,0.808 respectively.MEDIC: the ICC of cervical spinal cord gray matter were 0.665.(5)The comparison between the data automatic measured by SCT and manual measured by the radiologist(P1),T2/SPACE: the ICC of spinal cord area,right-left diameter,anterior-posterior diameter were 0.929,0.890 and 0.640.MEDIC: the ICC of cervical spinal cord gray matter were0.603.(6)The comparison between the data automatic measured by SCT and manual measured by the radiologist(P2),T2/SPACE: the ICC of spinal cord area,right-left diameter,anterior-posterior diameter were 0.907、0.890 and 0.682.MEDIC: the ICC of cervical spinal cord gray matter were 0.634.Conclusion:(1)Transverse MEDIC were significantly better than T2 WI and PDWI in the display of gray matter,and it can be used in conventional MR examination.(2)Quantitative analysis of spinal cord on the basis of T2/SAPCE have better consistency,however,quantitative analysis of cervical spinal cord on the basis of MEDIC were general.