The Clinical Study Of Ultrashort Time Echo Magnetic Resonance On Lumber Intervertebral Disc Degeneration

Research BackgroundIntervertebral disc degeneration(IVDD)is currently considered to be a series of cascade reactions under various mechanisms,such as biochemistry,pathophysiology,and biomechanics,due to natural aging and multiple factors.The result is the premise and pathological basis of degenerative osteoarthropathy of the spine,and it is also one of the major causes of low back pain(LBP).At present,the main clinical lumbar spine examination methods include X-ray,CT,and MRI.The main problems are now concentrated on the above imaging methods which can not be a good imaging of the all parts of the disc structure.The morphological changes are as a result of late intervertebral disc degeneration,but the early diagnosis of intervertebral disc degeneration is limited.Due to high resolution of soft tissue,no radiation and no overlapping images,MRI is currently the most important imaging method for lumbar spine.Because the cartilage endplate and annulus fibrosus are short T2 tissue(<10ms)in the intervertebral disc tissue,the nucleus pulposus is a long T2 tissue.Because the echo time(TE)is too long in conventional T2WI sequence,the short T2 tissue signal has decayed to 0 or close before the system.The cartilage endplate,annulus fibrosus show low or no signal.It is difficulty for showing their morphological integrity of the short T2 tissue.With the continuous development of imaging technology,ultrashort time of echo(UTE)MRI technology can shorten TE time and achieve short T2 tissue signal acquisition.It is a new technology that can display short T2 tissue.It provides a new research direction for the display of intervertebral disc tissue structure and the display of disc degeneration.This study was divided into two parts.In the first part,the MR-UTE technique showed a contrastive study of the anatomical structure of the intervertebral discs.Compared conventional magnetic resonance sequences T1WI,T2WI with the first image of dual-echo ultrashort time(UTE-1ST)and the post-sub image of dual-echo ultrashort time,semi-quantify the anatomical structural clarity scores of normal disc structures,quantify the SNR and CNR of each intervertebral disc and paravertebral tissue structure to figure out their advantages and characteristics of normal lumbar intervertebral disc structure.In the second part,MR-UTE technique studies the degenerating disc structure imaging.By scannint T1WI,T2WI,and MR-UTE double-echo sequence scans in with or without low back pain degenerative lumbar disc patients,it was analyzed whether there were relativity or not of low back pain on the degree of lumbar intervertebral disc degeneration.The influence of the structural integrity and integrity distribution of the cartilage endplates,annulus fibrosus,and bony endplates in the sequence were analyzed on MR-UTE technique.The structural integrity and integrity distribution were compared to determine the correlation between cartilage endplates,annulus fibrosus,bony endplates with intervertebral disc degeneration in the MR-UTE double echo sequence for a systematic and comprehensive understanding of disc degeneration.Imaging findings provide an earlier and more accurate diagnostic basis for the clinic.Chapter 1 Comparative Study of Anatomical Structure of Intervertebral Discs by UTE TechniqueObjectiveThrough routine T1WI and T2WI magnetic resonance techniques and MR-UTE double echo technique,the human lumbar intervertebral disc was studied.The advantage of short-echo T2 tissue display by MR-UTE dual echo technique was used to compare the structure of lumbar intervertebral discs.The advantages and characteristics of the anatomical structures of the lumbar intervertebral disc in the conventional T1WI and T2WI magnetic resonance techniques,the first UTE echo image in the MR-UTE double echo technique,and the UTE image for further discussion of the MR-UTE double echo technique the structure of the degenerative disc to lay the foundation.Materials and MethodSubjects:17 healthy volunteers,7 males and 10 females,aged 20-24 years,mean age 22.06±1.029 years,weight 39-90 kg,average weight 56.53±12.87 kg,height 153-183cm,average height 154.41 ±9.13cm.No obvious clinical symptoms,no trauma,no surgery,no history of any disease related to the spine.Imaing Techniques:Using a GE 3.0T 750w magnetic resonance imaging system for acquisition,a full spinal coil was used.Subjects were supine and advanced.The positioning line was positioned at the level of the third lumbar spine and entered the magnet.The scan site included the entire lumbar spine and ranged from T12/L1 to L5/S1 discs.Each patient underwent routine sagittal T1WI,T2WI,and UTE double echo sequences.Image post-processing,data measurement and evaluation methods:UTE raw image post-processing is performed using the post-processing subtraction(SUB)in the GE AW 4.6 Workstation,ie,with two different TE acquisitions within a time repetition(TR),the image is subtracted the second echo time image from the first echo time image to obtain tissue information with a relatively large change in T2/T2*attenuation during the ultra-short TE time.The two independent observers were used to measure and calculate the signal to noise ratio(SNR)and contrast to noise ratio(CNR)of each tissue structure in lumbar intervertebral discs.The image clarity was evaluated by the 5-fold Likert lumbar disc tissue structure.Statistical Methods:SPSS 19.0 software was used for statistical analysis.Measured data adopts mean±standard deviation.The data obtained from the two groups of images were used to compare the SNR,CNR,and image anatomical structures(nucleus pulposus,annulus fibrosus,cartilage endplate,vertebral bodies,and cerebrospinal fluid)of each tissue structure using ANOVA.The Kappa value was used to evaluate the consistency among the observers.Kappa ≥ 0.75 indicates that the consistency is good;0.4 ≤ Kappa<0.75 indicates that the agreement is normal;Kappa<0.4 indicates that the consistency is poor.The test standard a = 0.05,when P<0.05,considered statistically significant.Results1.To observe the images of UTE-1ST and UTE-SUB at the junction of the vertebral body and intervertebral disc in the lumbar spine.Observe the direct display of the cartilage endplate and distinguish it from the nucleus pulposus and vertebral endplate structure.The structure between the vertebral bodies is shown more clearly.2.The clarity of T2WI in nucleus pulposus,annulus fibrosus and spinal canal structure is higher than other sequences in semi-quantitative analysis of image clarity of lumbar spine.UTE-1ST and UTE-SUB are superior to T1WI and T2WI in cartilage endplate resolution.The difference was statistically significant(P<0.05).There was no significant difference between the sequences of the vertebral body,vertebral endplates,and muscle structural clarity(P>0.05).3.The quantitative SNR analysis of lumbar vertebral sequence images showed that the SNR of T1WI was higher than that of other sequences in all anatomical structures of the lumbar spine.UTE-SUB was the lowest other sequence in the SNR of the lumbar spine,and the T2WI sequence was in the nucleus pulposus and vertebral body.SNR is higher than UTE-1ST,SNR of UTE-1ST in cartilage endplate is higher than that of T2WI,and the difference is statistically significant(P<0.05).There is no difference in SNR between T2WI and UTE-1ST in vertebral body endplate and fiber ring SNR.Statistical significance(P>0.05).4.CNR quantitative analysis of lumbar spine sequence images CNR in T1WI,T2WI in CNR was higher than UTE-1ST in nucleus pulposus-annulus fibrosus,vertebral endplate-vertebral body,nucleus pulposus-endplate,and annulus fibrosus-vertebral body.UTE-SUB,UTE-1ST were higher in the CNR of cartilage endplate-vertebral than T1WI,T2WI.UTE-SUB was higher than UTE-1ST the CNR in nucleus pulposus-cartilage endplate.The above differences were statistically significant(P<0.05).ConclusionIn summary,the two images of UTE-1ST and UTE-SUB in the MR-UTE double echo sequence are superior to the conventional sequences T1WI and T2WI in the direct display of the cartilage endplate,and increase the nucleus pulposus-cartilage endplate-bone inter-tissue contrast between endplates,with UTE-1ST images showing an annulus fibrosus,bony endplates over UTE-SUB,UTE-SUB images at the annulus fibro-endochondrial,cartilage endplate-bone endplate interfaces.The cartilage endplate was superior to UTE-1ST in the cartilage endplate-nucleus pulposus interface.There was no obvious advantage in the display of other structures compared to conventional magnetic resonance sequences T1WI and T2WI.Chapter 2 MR-UTE for the Imaging Study of Degenerated Disc StructureObjectiveThe conventional magnetic resonance technique T2WI and MR-UTE dual echo techniques were used to study whether lumbar intervertebral disc degeneration patients with or without back pain symptoms.The advantages and value of MR-UTE double echo technique in displaying the degenerated disc structure were observed,and the low back pain was analyzed.Whether the symptoms have influence on the degree of lumbar intervertebral disc degeneration on the T2WI sequence.The structural integrity and integrity of distribution of cartilage endplate,the annulus fibrosus,the structural in the MR-UTE double echo sequence.The degree of degeneration of the disc on the T2WI sequence was analyzed.To compare the structural integrity and integrity of cartilage endplates,annulus fibrosus,and bony endplates with MR-UTE double-echo sequence.The extent of intervertebral disc degeneration was explored.The significance of UTE technique in the study of intervertebral disc degeneration was discussed.The development process and mechanism of disc degeneration were further studied.Materials and MethodSubjects:A total of 80 examiners were included after inclusion and exclusion criteria,including 29 males and 51 females,aged 22-80 years,mean age 50.66± 11.65 years,height 140-180cm,average height 162.08±7.35 years,Weight 45-88kg,average weight 60.85±9.69kg,divided into two groups according to whether there is lower back pain,group with lower back pain is A group,a total of 68,including 24 males and 44 females,aged 22-80 years old,The average age is 50.93± 11.82 year,height is 140-180cm,average height is 162.01±7.38cm,weight is 45-88kg,average weight is 60±9.407kg,and group without lower back pain is group B,total 12 people,including 5 males and 7 females,aged 31 to 68 years,mean age 49.17±10.58 year,height 155～179cm,average height 162.42±7.17cm,weight 50～85kg,average weight 65.67±9.92kg.The inspection method and image post-processing are the same as those in the first chapter.Image analysis:A total of 400 intervertebral discs were obtained for 80 examiners.The Pfirrmann graded method was used to grade the disc degeneration on the sagittal T2WI images.The UTE cartilage endplate was used to perform the UTE first echo image combined with subtraction images.The integrity and integrity of the annulus fibrosus and bony endplates were analyzed on the up and down distribution of the intervertebral discs.Statistical methods:All data analysis uses SPSS19.0 software system.Count data is expressed as a percentage of occurrences.The comparison between the two categorical variable constituents was performed using the R*C contingency table chi-square test.The modified Bonferroni method was used for multiple comparisons among the groups.The association analysis of the two categorical variables used the Kendall’s rank correlation analysis.The Kendall’s coefficients ranged from-1 to 1.Between the two,the greater the absolute value,the stronger the correlation,Kendall’s coefficient ≥ 0.7,indicating strong correlation;0.4 ≤ Kendall’s coefficient<0.7,indicating moderate correlation;Kendall’s coefficient<0.4,indicating weak correlation.All test levels a = 0.05,P<0.05 considered statistically significant.Results1.There was no statistically significant difference in the degree of disc degeneration between the two groups according to Pfirrmann’s classification of T2WI sequence(P>0.05).There was no significant correlation between the degree of degenerative disc and low back pain.2.There was no statistically significant difference in the composition ratio of cartilage endplates and bony endplates between the two groups(P>0.05).There was a statistically significant difference in the structural integrity of the annulus fibrosis between the two groups(P<0.05).The proportion of non-pain groups in the pain group and partially disappeared group was higher in the structurally complete disappearance group between the two groups.The difference was statistically significant(P<0.05).There was no significant difference in the composition ratio between the two groups(P>0.05).3.There was no statistically significant difference in the structural integrity of cartilage endplates,annulus fibrosus,and bony endplates between the two groups(P>0.05).The proportion of incompleteness on both sides was the highest,and only one side had the smallest proportion.4.There was a correlation between different groups of degenerative degrees of intervertebral discs on the T2WI sequence between integrity and integrity structural of the cartilage endplates,annulus fibrosus and the bony endplates in MR-UTE sequences.Kendall’s tau-b ranged from 0.502 to 0.602,showing moderate correlation.Conclusion1.The low back pain had no significant influence on the extent of intervertebral disc degeneration on T2WI.It had little effect on the integrity and integrity distribution of cartilage endplates,bony endplates,and integrity of the annulus fibrosus on the MR-UTE double echoes.Affects the integrity of the fiber ring distribution.2.There was a positive correlation between the degree of completeness and integrity of cartilage endplates,annulus fibrosus,and bony endplates in different degrees of degenerated intervertebral discs.The higher the degree of disc degeneration was,the higher the integrity of cartilage endplates,annulus fibrosus,and bony endplates disappeared partially,and both sides were mainly intact in MR-UTE double echo sequence.