Correlations Between Quantitative T2 And T2* MRI In A Diabetic Rabbit Lumbar Intervertebral Disc Degeneration Model

Objective: 1.To explore the diagnostic value of T2 mapping and T2 * mapping imaging for intervertebral disc degeneration;2.To explore the effect of diabetes on rabbit degeneration of the intervertebral disc,compare the value of T2 mapping and T2* mapping in the longitudinal follow-up of intervertebral disc degeneration.Methods:Thirty New Zealand white rabbits were randomly divided into normal control group(15 rats)and diabetic model group(15 rats).Diabetes model group and control group were randomly divided into three groups according to time: 1 month group(5 rats),3 months(5 rats),6 months group(5 rats).MRI was performed including Sagittal T2 WI,T2-spair,T2 mapping and T2* mapping.The degree of IVD degeneration was acroscopically assessed using the Thompson grading system.After image post-processing,measure the T2 and T2* values of the nucleus pulposus of L6/7 and L7/S1 intervertebral discs.All specimens were cut for hematoxylin and eosin,and safranin-O.Degenerative scoring of nucleus pulposus on HE stained sections with reference to the degenerative grading scale proposed by Masuda.Statistical analysis of differences in T2 value,T2* value and Thompson classification of histological degeneration scores of different nucleus pulposus.The differences of nucleus pulposus histological score,nucleus pulposus T2 value and T2* value between the control group and the diabetic model group were analyzed.Results: 1.There was significant difference in the T2 value of nucleus pulposus with different histological scores(F=101.1,P<0.05).There were significant differences in the nucleus pulposus scores between 2 and 4,3 and 4(P<0.05).There was no significant difference between the nucleus pulposus degeneration scores 2 and 3,5 and 6 points(P>0.05).The nucleus pulposus score was highly negatively correlated with T2(r=-0.794,P<0.01).2.There was a statistically significant difference in the T2* value of the nucleus pulposus with different histological scores(F=24.13,P<0.05).There was no significant difference between the pathological scores of 2,3 and 4(P>0.05).The difference between the scores of 5 and 6 was statistically significant(P<0.05).The nucleus pulposus score was moderately negatively correlated with T2* values(r=-0.615,P<0.01).3.The nucleus pulposus score was highly positively correlated with Thompson grade(r=0.641,P<0.01).4.Compared with the model group,the nucleus pulposus score,T2 value and T2* value were not statistically significant in the 1 month.In the 3 month,the nucleus pulposus score and T2 value were statistically different.There was no statistically significant difference in T2* values.At 6 months,there were statistical differences in histological scores,T2 values,and T2* values.Conclusion: 1.The T2 and T2* values of nucleus pulposus decrease with the increase of histological degeneration score;T2 value can sensitively reflect the changes of nucleocapsid proteoglycan.2.Conventional MR-based Thompson grading is not able to quantitatively and objectively evaluate disc degeneration.Both T2 mapping and T2* mapping imaging techniques can objectively and quantitatively reflect degeneration of the intervertebral disc.T2 mapping is more sensitive to early diagnosis of intervertebral disc degeneration than T2* mapping imaging.It is an effective means to evaluate intervertebral disc degeneration in vivo and non-invasively.3.Diabetes can accelerate the degeneration of the intervertebral disc.Compared to T2* mapping,T2 mapping imaging technology is more sensitive to the identification of accelerated disc degeneration of diabetes.