| ObjectiveImaging technique using T2 relaxation time Map of Magnetic Resonance（T2-mapping）was conducted for Non-invasive measurement of the contents of water molecules and collagen fibers in cartilage tissue after meniscus injury.T2 value of meniscus was calculated and combined with sagittal proton compression sequence.（FS-PDWI）The abnormal signal of meniscus was graded by Stoller,that is,I,Ⅱ and Ⅲ grade abnormal high signal.The T2 value of meniscus in three groups was analyzed,and the correlation between T2 value of meniscus and Stoller grade was analyzed by Pearson correlation analysis.Using arthroscopy as the gold standard,the accuracy of magnetic resonance T2-mapping quantitative technique in diagnosing meniscus tear was analyzed,and the ROC curve was drawn.The ROC curve was used to evaluate the diagnostic efficacy of T2 value for meniscus tear and to analyze the optimal diagnostic threshold for differentiating tear and degeneration of meniscus.According to the results of arthroscopy,the subjects were divided into tear group and degenerative group,and the T2 value of normal meniscus was measured to analyze the difference of T2 value among normal meniscus,tear group and degenerative group.The degree of meniscus injury was evaluated with T2-mapping quantitative technique in order to reduce unnecessary invasive examination and guide clinical treatment.Materials and methods1.The correlation research of meniscus injury classification using T2-mapping quantitative technique and PDWI-FS sequence.From October 2016 to January 2018,72 cases of meniscus injury,grade I,grade Ⅱ and grade Ⅲ,were studied prospectively in the Department of Imaging,Department of MRI,first affiliated Hospital of Guangzhou University of traditional Chinese Medicine,of which 20 cases were grade I.There were 28 cases of grade Ⅱ and 24 cases of grade Ⅲ.The age of the subjects ranged from 18 to 40 years old,with a median age of 29 years.Inclusion criteria:（1）All subjects had a history of knee joint pain and discomfort.（2）Weighted in the normal range,according to the BMI index,or body mass index（Referred to as body mass index,English is Body Mass Index,referred to as BMI,is calculated as BMI=Kg/ square meters）The normal reference range of BMI was 18.50.23.9;（3）No magnetic resonance（MRI）Check for contraindications.Exclusion criteria:（1）Previous history of knee joint surgery;（2）Abnormal meniscus development,such as discoid meniscus;（3）There are gout,rheumatoid arthritis and other basic lesions.The experiment passed the examination of the ethics committee of our hospital,and all the subjects signed the informed consent.GEHDxt3.0T high field magnetic resonance scanner was used to detect 15 channel surface coils of knee joint.MRI scans included common sequences and physiological sequences.Conventional scanning sequences included sagittal proton lipid sequences（FS-PDWI）Sagittal T1 WI sequence,coronal T 2 compression sequence（FS-T2WI）,its scanning parameters were: sagittal proton lipid sequence（FS-PDWI）:TR 2717.0ms,TE 40.0ms,FOV 170X170 mm,matrix 320 x 224,scanning time 2min16 s,layer thickness 4mm;Sagittal position T1WI:TR 884.0ms,TE 13.9ms,FOV 170 x 170 mm,matrix 384X256,scanning time 2min45 s,layer thickness 3mm;Coronal FS-T2WI:TR 2000.0ms,TE 60.0ms,FOV 170 x 170 mm,matrix 320 x 256,scanning time II,layer thickness 3mm.The physiological sequence was sagittal T2 mapping sequence,and its scanning parameters were as follows:Tr 1000.0ms te 6.5ms FOV170X170 mm,matrix 320X256,scanning time 8min36 s,slice thickness 3mm.The position of the scanning body was in the supine position,and the flexion of the knee joint was 15 degrees.To reduce the effect of exercise on the T2-mapping sequence,all patients were asked to sit still for 30 minutes before the scan,with scanning time fixed at 20:Between 00-22: 00.All subjects remained at rest for one week before the examination.After scanning,the T2-mapping image was uploaded to the workstation for post-processing,and the T2-mapping pseudo-color image was generated automatically.The best display plane of meniscus was selected by combining sagittal FS-PDWI and coronal FS-T2 images.Manually select the region of interest on the T2-mapping pseudo-color map（ROI,region of interest）The choice of ROI was abnormal signal region on meniscus.The signal of meniscus was classified by Stoller method.Grade 0,normal meniscus with uniform low signal and regular meniscus shape;In grade I,the meniscus was punctate and speckled,but not connected with the articular surface.Grade Ⅱ,the meniscus had linear hyperintense shadow,extending to the meniscus of the articular capsule,but not to the edge of the meniscus articular surface;Grade III,meniscus hyperintense shadow extending to the articular surface（The third level signal can be divided into two kinds: III A and III B.The third grade a signal is high signal and it communicates with the upper articular surface or interconnects with the lower joint surface.The third level B signal is high signal and can reach the upper two joints.）.The T2 relaxation time of abnormal high-signal region in meniscus was measured manually.In order to ensure the identity of the measured values,all the measurements were done by the same experienced imaging diagnostics.The statistical analysis and calculation were carried out with SPSS22.0,and the measurement data were expressed with the mean standard deviation of mean number.Single factor analysis of variance（Analysis of variance,ANOVA）The T 2 value of signal meniscus of grade I,Ⅱ and Ⅲ was compared.LSD-t test was used to compare the T2 value of the meniscus between the three groups（P < 0.05,P < 0.05）.If the difference was statistically significant,then use Pearson correlation analysis to study the correlation between T2 value and each stoller grade.2.Diagnostic study of T2-mapping quantitative technique for meniscal tearsIn this study,arthroscopy was performed on meniscal meniscus,which showed grade Ⅱ and Ⅲ signals on MRI in these subjects.At the same time,20 healthy volunteers were selected as the normal control group.All the damaged meniscus were diagnosed by using T2-mapping quantitative technique.The results of arthroscopy were taken as the gold standard,and the operating characteristic curve（ROC curve）of the subjects was adopted.（（Receiver operator characteristic curve,ROC）to test the diagnostic value of magnetic resonance T2-mapping sequence for meniscal tears,and calculate the area under the curve（AUC,Area Under Curve）.）To analyze the accuracy of diagnosis of meniscus tear,and to calculate the diagnostic threshold of T2-mapping quantitative technique for diagnosis of meniscus tear.（Cut of value）To identify meniscus degeneration and tear.According to the results of arthroscopy,the injured meniscus was divided into tear group and degenerative group.The difference of T2 value between tear group,degenerative group and control group was statistically significant（P < 0.05）.Results1.The correlation research of meniscus injury classification using T2-mapping quantitative technique and PDWI-FS sequence.The T2 value of meniscus injury in I class signal group,class II signal group and class III signal group was 23.57 + 2.,respectively.15.31.6 + 1.93.The difference between the two groups was 46.38 + 1.84,and the difference between the two groups was statistically significant（F value =403.439,P<0.001）。The T2 value of the meniscus of the class III signal was the largest,and the T2 value had a significant correlation with the Stoller classification,and the correlation coefficient r=0.946（When confidence was 0.01,the first correlation was significant）;The T2 value was positively correlated with the Stoller grade,that was,the higher the signal level,the larger the T2 value of the corresponding meniscus,the difference was statistically significant（P < 0.001）.2.Diagnostic study of T2-mapping quantitative technique for meniscal tearsWith arthroscopy as the gold standard,the sensitivity of conventional magnetic resonance sequence to meniscus tear was 86.4%.The specificity is 83.3%.The false negative rate was 13.6%.The false positive rate was 16.7%.The sensitivity of magnetic resonance T2-mapping quantitative technique in the diagnosis of meniscus tear was 95.5%.The specificity was 93.3%.The false negative rate was 4.5%.The false positive rate was 6.7%.The sensitivity and specificity of T2-mapping in the diagnosis of meniscus tears were higher than those in conventional sequences.Draw ROC curve,area under curve（AUC,Area Under Curve）The diagnostic threshold for differential diagnosis of meniscus tear and degeneration was 38.11.T2-mapping sequence was of high diagnostic value in diagnosing meniscus tear.When the T2 value was greater than 38.11,the meniscus tear could be diagnosed as lower than 38.11.Even if the signal of grade Ⅲ appeared in the conventional sequence,it was also diagnosed as meniscus degeneration.With the results of arthroscopy as the gold standard,the subjects were divided into tearing and denaturing groups,and the T2 values of the normal control group,the denatured group and the tearing group were 18.25 + 1,respectively.7.32.04 + 2.79.45.1 + 1.93,the difference of T2 value 22 between the three groups were all different,and the difference was statistically significant（F value =383.938,P <0.05）。 Conclusions1.The correlation research of meniscus injury classification using T2-mapping quantitative technique and PDWI-FS sequence.Magnetic resonance T2-mapping quantitative technique could be used to measure the changes of tissue composition after meniscus injury,that is,the content of water molecules and collagen fibers,which could be reflected by T2 relaxation time,that is,T2 value.The meniscus with Stoller grade Ⅲ signal had the highest T2 value and the lowest meniscus T2 value.T2 was positively correlated with the grade of Stoller grade.T2 value was sensitive to the change of meniscus composition,which was helpful for early detection of lesions and assessment of injury degree.2.Diagnostic study of T2-mapping quantitative technique for meniscal tearsThe diagnostic value of MRI T2-mapping for meniscus tear was higher than that of conventional sequence,and the sensitivity and specificity of MRI were higher than those of conventional sequence.The diagnostic threshold for differential diagnosis of meniscus tear and degeneration was 38.11.The T2 values of normal control group,tear group and degenerative group were all different,and the difference was statistically significant.In this study,the T2-mapping quantitative technique was used to measure the T2 relaxation time,to observe the change of tissue composition in meniscus,to evaluate the pathological changes of meniscus early,and to analyze and calculate the diagnostic threshold,which could help to distinguish the tear of meniscus.Avoid unnecessary arthroscopic invasive examination and guide clinical treatment.Magnetic resonance T2-mapping quantitative technique had high diagnostic value and noninvasive advantages.It could be used as an impoortant supplement of conventional sequence. |
PDF Full Text Request