The Correlation Between The Degree Of Meniscus Injury And The T1 Rho And T2 Mapping Of The Articular Cartilage

ObjectiveIn this study,we scanned the patients’knee joint who have osteoarthritis,using Quantitative MRI(q MRI)techniques:T1rho and T2 mapping sequences,to quantitative evaluate the microstructure damage before articular cartilage morphological change,and then discussed the relationship between them and the classification of meniscus injury.In order to provide more intuitive diagnostic basis for the early stage of osteoarthritis of the knee joint in clinical work.MethodsSubjects:Selected 80 patients with osteoarthritis of the knee joint,in Qingdao Municipal Hospital,during December 2016-October 2017.There were 30 males and 50females,aged 47-76 years old,with an average age of 54.31 years.Equipment:Using 3.0T MRI device(GE MR 750)and knee coil(HD TR knee)to complete the inspection.The patients were taken supine position,scan left knee or right knee.The foot was advanced.The knee joint was extended.The inferior border of the patella was the scanning center.The scanning range from the superior edge of the patella to the tibial plateau.The routine sequences(T1WI,FS PDWI)of the knee joint was scanned.The patient should remain calm 20 minutes before the MRI examination,because exercise or weight can lead to a change in articular cartilage,resulting in inaccurate results.Because of the anatomic variation in the anterior horn of the meniscus,the meniscus anterior horn of some patients is not clear,so we only chose the posterior horn of meniscus for study.A double-blind method was adopted.Two radiologists who had more than 10 years’working experience were independently diagnosed with routine MRI sequence images,and the degree of meniscus injury was graded.The classification of meniscus injury used Stoller’s grading.Then using the 3.0T MRI device(GE MR 750)to scan the unconventional sequence T1rho and T2 mapping of the knee joint,and using GE ADW 4.6 workstation functool software to process the images.In the center of the posterior horn of the meniscus,selected 4regions of interest of 1 mm~2(ROI)and and taking the mean value as the T1rho and T2value of the cartilage in the area.The area of the articular cartilage included the medial femoral condyle(MFC),the lateral femoral condyle(LFC),the medial tibial plateau(MTP)and the lateral tibial plateau(LTP).All data were statistically analyzed with SPSS 24.0software,and the measured data were expressed as(mean±standard deviation,`x±s).The difference of T2 and T1rho between different groups was analyzed by single factor variance analysis(ANOVA),and the difference between the two groups was compared with the LSD-t method.Test standards P<0.05.Pearson correlation analysis was used to analyze the correlation between the articular cartilage’s T2 and T1rho value.ResultsAll the patients were examined.All the 80 patients were enrolled to analyze with good image quality.The enrolled patients include 50 female,30 male,a total of 160 meniscus.We have 12 normal meniscus,accounting for 7.5%,corresponding to different regions’cartilage(MFC,MTP,LFC,LTP)T1rho relaxation time was(31.37±3.68,31.76±2.99,33.16±4.43,35.85±4.47)ms,corresponding to different regions’cartilage(MFC,MTP,LFC,LTP)T2 relaxation time was(31.31±3.43,31.53±2.31,36.50±4.75,33.10±5.65)ms;45 meniscus for I degree,accounting for 28.2%,corresponding to different regions’cartilage(MFC,MTP,LFC,LTP)T1rho relaxation time was(41.16±5.32,39.87±4.40,40.80±5.52,41.85±5.58)ms,corresponding to different regions’cartilage(MFC,MTP,LFC,LTP)T2 relaxation time was(37.12±4.16,36.91±4.97,39.77±5.79,36.68±4.73)ms;62 meniscus for II degree,accounting for 38.7%,corresponding to different regions’cartilage(MFC,MTP,LFC,LTP)T1rho relaxation time was(49.06±5.71,47.03±4.79,45.88±4.42,46.38±4.59)ms,corresponding to different regions’cartilage(MFC,MTP,LFC,LTP)T2 relaxation time was(47.12±5.75,43.61±5.71,44.23±4.60,43.74±4.49)MS;41 meniscus for III degree,accounting for 25.6%,corresponding to different regions’cartilage(MFC,MTP,LFC,LTP)T1rho relaxation time was(56.61±5.84,52.40±5.59,55.85±7.70,50.73±6.73)ms,corresponding to different regions’cartilage(MFC,MTP,LFC,LTP)T2 relaxation time was(52.64±6.47,49.53±5.23,52.05±6.56,49.66±6.44)ms.1.With the improvement of meniscus grading,the T1rho value of adjacent articular cartilage increased.The T1rho relaxation time of articular cartilage differed significantly between different meniscus grading(0,I,II,III),and the difference was statistically significant(P<0.05).2.With the improvement of meniscus grading,the T2 value of adjacent articular cartilage increased.Make a comparison between meniscus grading I and 0,corresponding to each area of articular cartilage was no significant difference between T2 values;The grade II and III of meniscus were compared with grade 0 and I respectively.There was significant difference in the T2 value of articular cartilage in each region,and the difference was statistically significant(P<0.05);Make a comparison between meniscus grading II and III,the T2 values of articular cartilage in the corresponding regions were different,and the difference was statistically significant(P<0.05).3.Pearson correlation analysis was use to analyze the correlation between the articular cartilage’s T2 and T1rho value.In MFC,MTP,LFC,LTP,T1rho and T2 in articular cartilage of the correlation coefficient r values were 0.7,0.69,0.67,0.60,can be think there is a positive correlation between the articular cartilage,and the correlation is more significant.Conclusions1.Those OA patients of knee,92.5%(148/160)of them had different degrees of meniscus injury.It can be considered that OA patients will suffer from meniscus injury to a large extent.2.With the increase of meniscus injury grading,the T1rho and T2 values of articular cartilage was increasing,we can think that meniscus injury will lead to the weakening of cartilage protection and finally cause the injury of articular cartilage.With the increase of meniscus injury grading,the more serious the articular cartilage injury.Therefore,before articular cartilage morphology changes,we can evaluate articular cartilage injury according to meniscus injury condition,which is of great clinical significance for early intervention treatment of OA patients.3.T1rho and T2 mapping can be used for the quantitative study of articular cartilage injury of knee joint in patients with OA,which has a certain relevance.Because they reflect different substances in articular cartilage,the proportion of related substances in articular cartilage is different,which leads to different sensitivity to articular cartilage quantitative measurement.In this study,the T1rho value of articular cartilage was significantly different between meniscus grading I and 0.It can be considered that T1rho sequence is more sensitive to articular cartilage injury.4.T1rho and T2 mapping technique of articular cartilage as noninvasive MRI quantitative analysis method,it should be widely applied to clinical practice,but these two methods can not be used as a diagnostic tool of articular cartilage injury in the knee independently,it should be combined with conventional morphology(T1WI,T2WI)examination of the articular cartilage,to make qualitative description of articular morphol ogy and meniscus injury,so that the diagnosis of OA is more persuasive.