| ObjectiveTo explore the application value of the area ratio of cervical spinal cord to dura sac and DTI with 3.0T MRI scanner in normal cervical spinal cord.Materials and methods27 healthy volunteers were selected as subject objects,including 15 male cases and12 female cases,aged from 20 to 69 years with an average age of 41.5.They were divided into three age groups : 30 years old and the less for the young group(11cases),31 to 60 years old for the middle aged group(10 cases),61 years old and the more for the older group(6 cases).All healthy volunteers,with no history of neurological disorders and any positive clinical symptoms and also revealed no abnormalities on conventional MRI examination.Conventional sagittal T2 WI and T1 WI together with axial T2 WI and DTI of cervical spinal cord were perform in all the objects by using Philips Achieva 3.0T MR.A 16-channel head and neck joint phased array surface coil was accepted.DTI scanning were performed using SENSE technique combined with single-shot spin echo-echo planar imaging sequence, with diffusion sensitivity gradient in fifteen directions,diffusion weighting coefficients(b value)b=700s/mm2.The scanning range is from the top edge of C1 to the lower edge of T1,with a saturated zone both in front and rear of each cervical vertebrae and scanner time of 7′14″.The axial T2 WI images of each segment for each object were imported into Photoshop CS6.The pixel values of the spinal cord and the dura sac of each segment were measured by using the magnetic lasso tool,and the ratio was calculated 。All the raw data of DTI were transmitted into Philips workstation,corrected by the Register corrector to reduce image distortion.The disc corresponds to the level of the spinal cord were selected to analyze.The values of FA and ADC were measured at each level of the cervical spinal cord according the FA map and ADC map.Regions of interest(ROI)were manually set on FA maps and ADC maps,which should include the entire cervical spinal cord(gray and white matter).Diffusion tensor tractography of normal cervical spinal cord were obtained by using the Fiber tracking software.All the data of objects were measured by two experienced radiologists.All the data were analyzed by SPSS19.0 statistical package.The values of FA,ADC and the area ratio of cervical spinal cord to dura sac at the same level were compared with Independent-Samples T Test(Equal variances assumed)between male and female.The values of FA, ADC and the area ratio of cervical spinal cord to dura sac among different levels and different age groups were compared with ANOVA(Equal variances assumed) or Welch(Equal variances not assumed).If there were no statistical difference,the parameters were multiple compared.The significant statistical difference was set at P<0.05.Result(1) The conventional T2 WI and T1 WI,FA,ADC and diffusion tensor tractography images of all the normal cervical spinal cord revealed well.(2) There were no statistical difference in values of FA(F=1.072,P=0.373) and ADC(F=0.364,P=0.834) among C2/3,C3/4,C4/5,C5/6,C6/7 level of normal cervical spinal cord(P>0.05).There were significant statistical difference in values of the area ratio of cervical spinal cord to dura sac among C2/3,C3/4,C4/5,C5/6,C6/7 level of normal cervical spinal cord(P<0.05).However,There were no statistical difference in values of the area ratio of cervical spinal cord to dura sac among C3/4,C4/5,C5/6,C6/7 level of normal cervical spinal cord(P>0.05).The FA values had a downward trend from C3/4to C5/6 level,meanwhile,the ADC values had an upward trend from C2/3 to C6/7.The area ratio of cervical spinal cord to dura sac at C2/3 level were lowest,however,C4/5 and C5/6 were relatively higher.(3) There were no statistical difference in values of FA, ADC and the area ratio of cervical spinal cord to dura sac at C2/3,C3/4,C4/5,C5/6,C6/7 level between males and females(P>0.05).(4) There were no statistical difference in values of FA, ADC and the area ratio of cervical spinal cord to dura sac at the same level among different aged groups(P>0.05).(5) The average values of FA,ADC in all 27 volunteers were 0.716±0.026,(0.905±0.042)x10一3mm/S respectively. The average values of the area ratio of cervical spinal cord to dura sac at C2/3 level and other levels were0.354±0.042, 0.389±0.039 respectively.(6) The normal cervical spinal cord demonstrated homogeneous blue in cranial-caudal direction on diffusion tensor tractography.Conclusion(1) DTI technique and the quantitative analysis of the area ratio of cervical spinal cord to dura sac can be successfully applied in cervical spinal cord. the normal average values in normal cervical spinal cord were acquired,these data can provide important reference information for the pathophysiology studies of the spinal cord and the clinical diagnosis of the spinal diseases.(2) Age and gender had no significant effect in the values of FA、ADC and the area ratio of cervical spinal cord to dura sac at the same level in normal cervical spinal cord;The anisotropy and diffusion characteristics were nearly the same among different levels of normal cervical spinal cord. There were no statistical difference in values of the area ratio of cervical spinal cord to dura sac among different level except C2/3.The normal cervical spinal cord was a cylindrical diffusive tissue along nerve fiber.These information can provide important reference value to the study of normal spinal cord.(3) The diffusion tensor tractography can clearly and intuitively reveal white matter tracts in 3D.ObjectiveTo explore the application value of the area ratio of cervical spinal cord to dura sac and DTI with 3.0T MRI scanner in cervical spondylotic mylopathy.Materials and methods74 patients with cervical spondylotic mylopathy were selected as subjects,including 33 male cases and 41 female cases,aged from 28 to 88 years old with an average of 55.9 years.They were divided into three groups based on the changes of spinal cord compression on T2 WI images:dura sac compression alone for G1 group(38 cases,including 16 male cases and 22 female cases, aged from 28 to 77 with an average 52.7);spinal cord compression with no abnormality on T2 WI for G2group(27 cases,including 13 male cases and 14 female cases, aged from 41 to 88 with an average 58.6);spinal cord compression with hyper-intensity on T2 WI for G3 group(9cases,including 4 male cases and 5 female cases, aged from 46 to 82 with an average61.6).Conventional sagittal T2 WI and T1 WI together with axial T2 WI and DTI of cervical spinal cord were perform in all the objects by using Philips Achieva 3.0T MR.A 16-channel head and neck joint phased array surface coil was accepted.DTI scanning were performed using SENSE technique combined with single-shot spin echo-echo planar imaging sequence, with diffusion sensitivity gradient in fifteen directions,diffusion weighting coefficients(b value)b=700s/mm2.The scanning range is from the top edge of C1 to the lower edge of T1,with a saturated zone both in front and rear of each cervical vertebrae and scanner time of 7′14″.The axial T2 WI images of each segment for each object were imported into Photoshop CS6.The pixel values of the spinal cord and the dura sac of each segmentwere measured by using the magnetic lasso tool,and the ratio was calculated。All the raw data of DTI were transmitted into Philips workstation,corrected by the Register corrector to reduce image distortion.The disc corresponds to the level of the spinal cord were selected to analyze.The values of FA and ADC were measured at most seriously compressed level of the cervical spinal cord.Regions of interest(ROI)were manually set on FA maps and ADC maps,which should include the entire cervical spinal cord(gray and white matter).Diffusion tensor tractography of normal cervical spinal cord were obtained by using the Fiber tracking software.All the data of objects were measured by two experienced radiologists.All the objects were graded by JOA by two experienced orthopedist.All the data were analyzed by SPSS19.0 statistical package.Using the normal adults in part one as control group(group G0).The values of FA,ADC and the area ratio of cervical spinal cord to dura sac among control group and group G1、G2、G3 were compared with one-way ANOVA(Equal variances assumed).Pairwise comparisons of each parameter among four groups were performed by using Independent-Samples T Test(Equal variances assumed).The correlation test between JOA and the other three parameters were performed by using Multiple linear Regression test.The level of significance was defined as 0.05,while the significant statistical difference was set at P<0.05.Result(1) The conventional T2 WI and T1 WI,FA,ADC and diffusion tensor tractography images of all the normal cervical spinal cord revealed well.(2) There were statistical difference in values of ADC, FA, the area ratio of cervical spinal cord to dura sac among the control group G0 and group G1,G2,G3.(P<0.05).(3) There were statistical difference in values of FA,ADC, the area ratio of cervical spinal cord to dura sac among group G1,G2,G3 respectively(P<0.05)except the values of FA and the area ratio of cervical spinal cord to dura sac among group G2,G3(P>0.05) by pairwise comparison.(4) Correlation coefficients between FA,ADC, the area ratio of cervical spinal cord to dura sac and JOA were 0.510、-0.582、-0.363respectively(P<0.05).( P<0.05)(5) The diagnostic sensitivity of the value of FA,ADC, the area ratio of cervical spinal cord to dura sac were 82.4%(61/74)、83.8%(62/74)、75.7%(56/74)respectively,which were obtained by comparing with the results of chapter one.The federated diagnostic sensitivity of the three parameters was 98.6%;(6) Diffusion tensor tractography show varying degree of the distortion and break of cord on the compression levels in 3D.Conclusion(1) There were statistical difference in values of ADC, FA, the area ratio of cervical spinal cord to dura sac between the control group and group G1(P<0.05). This indicates that all of the three parameters are more sensitive than routine MRI in evaluating the early and mildly spondylosis-related changes of the cervical spinal cord.(2) There were statistical difference in values of ADC, FA, the area ratio of cervical spinal cord to dura sac among group G1,G2,G3 respectively(P<0.05)except values of FA and the area ratio of cervical spinal cord to dura sac among group G2,G3(P>0.05) by pairwise comparison. This indicates that the changes in the values of ADC, FA, can reflect the degree of cervical spinal cord injury to a certain extent.(3) The degree of correlation between the values of FA,ADC, the area ratio of cervical spinal cord to dura sac and JOA were moderate positive, moderate negative,weak negative,suggesting that the values of FA,ADC, the area ratio of cervical spinal cord to dura sac may reflect the clinical performance to some extent.(4) The diffusion tensor tractography could clearly and intuitively reveal the varying degree of the distortion and break of white matter tracts in the compression levels in 3D.(5) The descending order of diagnostic sensitivity of three parameters is followed by the values of ADC, FA, the area ratio of cervical spinal cord to dura sac respectively.The federated diagnostic sensitivity of three parameters is higher than one of the single parameter, suggesting that the joint use of three parameters can reflect cervical changes in the patients with cervical spondylotic mylopathy more comprehensively and systematicaly. |
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