Purpose To explore the consistency between T2 mapping and three-dimensional water-selective cartilage(3D-WATSc)sequence measurement of knee cartilage volume.Materials and Methods A total of 30 healthy volunteers were recruited and underwent 3D-WATSc and T2 mapping sequence scans of the left knee joint in the Affiliated Lihuili Hospital of Ningbo University from May to December 2022.A total of 20 subjects'T2 mapping sequences were randomly selected and eight groups of raw images with different TE(13,26,39,52,65,78,91,104 ms)were analyzed.The quality of the raw images was rated by two observers,and the consistency of two observers'scores were subjected by Kappa test.The TE value with the best image quality was determined via Welch analysis of variance and Games-Howell text post hoc test.Based on T2 mapping and 3D-WATSc sequences,semi-automatic segmentation measurements were performed on the cartilage volume of femoral condyle,tibial plateau and patellar posterior margin in 30 subjects.Intra group correlation coefficient(ICC)and Bland-Altman plot were used to test the consistency of cartilage volume between two observers under T2 mapping sequence,as well as between T2 mapping and 3D-WATSc sequences.Results The consistency of the scores of the two observers was moderate except for poor consistency at TE 104 ms(Kappa=0.318)and no statistical difference at TE 78 ms(P=0.052),with Kappa values greater than 0.40 and P<0.05,further analysis showed that the cartilage display quality score was optimal at TE 26 ms(M=2.90).Comparing TE 26 ms with the scores of the other seven groups in Games Howell text,except for TE 26 ms and TE 13 ms(M=2.55),TE 26 ms and TE 39 ms(M=2.62),which had no statistically significant difference in scores(P>0.05),there were significant differences in scores between TE 26 ms and the other TE groups(all P<0.05).On the T2 mapping(TR 2 000 ms,TE 26 ms)sequence,the ICC values of the cartilage volumes of each part segmented by two observers were all greater than 0.6,P<0.05,with the consistency of femoral condyle cartilage volume being the best(ICC=0.877,P<0.01).The consistency of the cartilage volumes of each part measured by 3D-WATSc and T2 mapping sequences was good(ICC>0.75,P<0.01),with the consistency of tibial plateau cartilage volume being the best(ICC=0.857,P<0.01).Conclusion The T2 mapping original grayscale image(TR 2 000 ms,TE 26 ms)can clearly display the morphology of knee joint cartilage,the consistency between T2 mapping and 3D-WATSc sequences in quantifying knee cartilage volume is good,and the T2 mapping single sequence provides a reliable scanning scheme for one-stop quantitative analysis of knee joint cartilage morphology and function.

Purpose To explore the consistency between T2 mapping and three-dimensional water-selective cartilage(3D-WATSc)sequence measurement of knee cartilage volume.Materials and Methods A total of 30 healthy volunteers were recruited and underwent 3D-WATSc and T2 mapping sequence scans of the left knee joint in the Affiliated Lihuili Hospital of Ningbo University from May to December 2022.A total of 20 subjects'T2 mapping sequences were randomly selected and eight groups of raw images with different TE(13,26,39,52,65,78,91,104 ms)were analyzed.The quality of the raw images was rated by two observers,and the consistency of two observers'scores were subjected by Kappa test.The TE value with the best image quality was determined via Welch analysis of variance and Games-Howell text post hoc test.Based on T2 mapping and 3D-WATSc sequences,semi-automatic segmentation measurements were performed on the cartilage volume of femoral condyle,tibial plateau and patellar posterior margin in 30 subjects.Intra group correlation coefficient(ICC)and Bland-Altman plot were used to test the consistency of cartilage volume between two observers under T2 mapping sequence,as well as between T2 mapping and 3D-WATSc sequences.Results The consistency of the scores of the two observers was moderate except for poor consistency at TE 104 ms(Kappa=0.318)and no statistical difference at TE 78 ms(P=0.052),with Kappa values greater than 0.40 and P<0.05,further analysis showed that the cartilage display quality score was optimal at TE 26 ms(M=2.90).Comparing TE 26 ms with the scores of the other seven groups in Games Howell text,except for TE 26 ms and TE 13 ms(M=2.55),TE 26 ms and TE 39 ms(M=2.62),which had no statistically significant difference in scores(P>0.05),there were significant differences in scores between TE 26 ms and the other TE groups(all P<0.05).On the T2 mapping(TR 2 000 ms,TE 26 ms)sequence,the ICC values of the cartilage volumes of each part segmented by two observers were all greater than 0.6,P<0.05,with the consistency of femoral condyle cartilage volume being the best(ICC=0.877,P<0.01).The consistency of the cartilage volumes of each part measured by 3D-WATSc and T2 mapping sequences was good(ICC>0.75,P<0.01),with the consistency of tibial plateau cartilage volume being the best(ICC=0.857,P<0.01).Conclusion The T2 mapping original grayscale image(TR 2 000 ms,TE 26 ms)can clearly display the morphology of knee joint cartilage,the consistency between T2 mapping and 3D-WATSc sequences in quantifying knee cartilage volume is good,and the T2 mapping single sequence provides a reliable scanning scheme for one-stop quantitative analysis of knee joint cartilage morphology and function.