Preliminary Study Of Magnetic Resonance T1p In Nucleus Pulposus Of Female Adolescent Idiopathic Scoliosis With Major Thoracolumbar Curvel At 3.0T MR

Background:the purpose of this study was to analyze T1p values in early degeneration of idiopathic thoracolumbar intervertebral disc(L1/2-L5/S1)in female adolescents.Material/Methods:Lumbar sagittal T2-weighed imaging,T1-weighed imaging and T1p relaxation time were performed at 3.0T MRI in 37subjects whose age were ranging from 10 to 18 years old and including L1-L2 to L5-S1 intervertebral discs.A total of 185 lumbar intervertebral discs were included in this study.In addition,20 healthy volunteers of the same age group were selected as the control group.In AIS patients,there was no any degeneration of the L1-S1 lumbar disc,in other words,The discs were all Pfirrmann class I for the A group.L4/5,or(and)L5/S1 degenerated were for B group.All intervertebral discs morphology were assessed and graded on the midsagittal T2WI of the lumbar spine to measure the T1p value of the nucleus pulposus.The intraclass correlation coefficients(ICC)was used to assess the reproducibility in two measurement of T1p relaxation times.The difference of T1p values of NP among the three groups were tested using the T test.ANOVA and Spearman rank correlation were applied to compare the difference of T1p values in disc segments.Results:The reproducibility between the two measurements for T1 p values in different regions of interest was excellent(ICC=0.905-0.913)The T1p values of lumbar intervertebral disc nucleus in normal volunteers were 139.5 ± 5.9 ms,and there was no significant difference in the T1p values of the disc nucleus in each section of L1-5(F=1.187,P=0.321).The mean and standard deviation of T1p values in group A and B were 129.31 ±2.83ms、123.80±9.07ms,The average value of T1p in nucleus pulposus of group B was significantly lower than that of group A.Both A and B were significantly lower than that of the normal control group(t=-17.294,P<0.01;t=-13.217,P<0.01).The results showed a significant difference in T1p values of NP among the different disc levels in group a and B,but not when comparing in normal group.In group B,T1 p value of Pm I grade was significantly higher than those of grade II and III(t = 7.277,P<0.01).conclusions:T1p relaxation time measurements can reflect the abnormal stress that on the early degenerative changes of lumbar intervertebral discs.T1p values are more sensitive than that of conventional T2WI image in the early changes of Proteoglycan in NP lumbar intervertebral disc tissue in AIS patients.