目的:基于MRI定量分析长途徒步拉练对大学生膝关节急性损伤及膝关节软骨亚区的影响。方法:入选2019年9月陆军军医大学新入学的27名男性青年大学生，年龄17~20（19.48±0.14）岁，均全程参加为期8 d、240 km的长途徒步拉练。在徒步前（基线测量）和徒步后1 d（随访测量）利用高场MRI对其右膝进行三维定量MRI。两名影像诊断医生评估膝关节急性损伤情况，包括半月板和软骨损伤（5分制）、骨髓水肿和韧带损伤及关节积液（3分制）。同时采用半自动软骨分割和三维数据后处理技术，测量股骨内外侧、胫骨内外侧等共21个亚区软骨体积、厚度和Tn 2值。利用配对双样本非参数检验及配对样本n t检验比较徒步前后膝关节软骨定量指标的变化。n 结果:膝关节急性损伤方面较徒步拉练前，拉练后分别有8和9名大学生新发了1~3级内、外侧半月板损伤；4名大学生的前交叉韧带损伤从0级发展到1级；10名大学生骨髓水肿从0级发展到2级，5名从0级发展到1级；5名大学生关节腔积液从1级发展为2级（均n P<0.05）。膝关节软骨亚区量化分析方面较徒步拉练前、拉练后，股骨滑车中心区体积增加［（1.84±0.32）mmn 3比（1.67±0.29）mmn 3］，股骨髁内侧中央区体积减小［（1.18±0.21）mmn 3比（1.26±0.17）mmn 3］，（均n P<0.05）；11个软骨亚区［（1.37±0.27）mm比（1.53±0.18）mm］、［（1.42±0.25）mm比（1.54±0.17）mm］、［（1.53±0.20）mm比（1.62±0.20）mm］、［（1.72±0.28）mm比（1.83±0.28）mm］、［（1.84±0.45）mm比（2.04±0.42）mm］、［（2.20±0.58）mm比（2.46±0.50）mm］、［（1.74±0.19）mm比（1.85±0.21）mm］、［（1.45±0.21）mm比（1.58±0.16）mm］、［（1.81±0.22）mm比（1.91±0.15）mm］、［（1.44±0.13）mm比（1.53±0.15）mm］的软骨厚度均较徒步前变薄（均n P<0.05）；有7个亚区［（40.57±26.23）ms比（67.10±47.46）ms］、［（80.10±20.56）ms比（98.42±23.58）ms］、［（87.92±24.95）ms比（108.84±29.24）ms］、［（50.49±19.18）ms比（76.97±37.16）ms］、［（38.89±15.82）ms比（69.70±40.16）ms］、［（55.84±24.53）ms比（106.35±50.01）ms］及［（72.38±36.64）ms比（105.31±39.34）ms］Tn 2值均较徒步前降低，而髌软骨两个亚区［（102.13±44.47）ms比（72.20±28.37）ms］、［（97.42±44.86）ms比（76.67±51.64）ms］Tn 2值较徒步前增高（均n P0.05）。n 结论:长途徒步拉练会导致青年大学生膝关节急性损伤产生。膝关节软骨亚区厚度整体均呈变薄趋势，而体积和Tn 2值则呈现不同的变化趋势。n “,”Objective:To assess the effects of long-distance march and training on acute knee injury and knee cartilage sub-regions of college students using quantitatively magnetic resonance imaging analysis.Methods:Twenty-seven young male students from freshman classes in the Army Military Medical University were enrolled in September 2019, aged from 17 to 20 (19.48±0.14) years, participated in the whole 8-day, 240 km long-distance march and training. Three-dimensional quantitative MRI was performed on the right knee using high-field MRI before (baseline) and 1 day after (follow-up) march. The assessment indexes included: meniscus and cartilage injury(5-point scale), bone marrow and ligament injury, and joint effusion(3-point scale). Using semi-automatic cartilage segmentation and 3D data post-processing techniques, a total of 21 sub-regions of cartilage volume and thickness were measured in the medial and lateral femur, medial and lateral tibia. Paired-samples t-test was used to compare the changes in quantitative cartilage indices of the knee joint before and after march.Results:In terms of acute knee injuries, medial and lateral meniscus injuries (grade 1-3) occurred in 8 and 9 college students, respectively compared with those before march. Anterior cruciate ligaments injury occurred in 4 college students and developed from grade 0 to grade 1. Bone marrow edema occurred in 10 students and developed from grade 0 to grade 2, and in 5 students from grade 0 to grade 1. Joint effusion occurred in 5 college students and developed from grade 1 to grade 2 (all n P<0.05). In terms of quantitative analysis of cartilage subregion of knee joint, the volume of central region of femoral pulley increased [(1.84±0.32) mmn 3 vs (1.67±0.29) mmn 3] and the volume of central region of medial femoral condyle decreased [(1.18±0.21) mmn 3 vs (1.26±0.17) mmn 3] compared with that before march (all n P<0.05); The cartilage thickness of 11 cartilage subregion [(1.37±0.27) mm vs (1.53±0.18) mm], [(1.42±0.25) mm vs (1.54±0.17) mm], [(1.53±0.20) mm vs (1.62±0.20) mm], [(1.72±0.28) mm vs (1.83±0.28) mm], [(1.84±0.45) mm vs (2.04±0.42) mm], [(2.20±0.58) mm vs (2.46±0.50) mm], [(1.74±0.19) mm vs (1.85±0.21) mm] [(1.45±0.21) mm vs (1.58±0.16) mm], [(1.81±0.22) mm vs (1.91±0.15) mm], [(1.44±0.13) mm vs (1.53±0.15) mm] was thinner than that before march (alln P<0.05). The Tn 2 values of 7 cartilage subregion [(40.57±26.23) ms vs (67.10±47.46) ms], [(80.10±20.56) ms vs (98.42±23.58) ms], [(87.92±24.95) ms vs (108.84±29.24) ms], [(50.49±19.18) ms vs (76.97±37.16) ms], [(38.89±15.82) ms vs (69.70±40.16) ms] [(55.84±24.53) ms vs (106.35±50.01) ms] and [(72.38±36.64) ms vs (105.31±39.34) ms] were lower than those before march, while the Tn 2 values of the two subregions of patellar cartilage [(102.13±44.47) ms vs (72.20±28.37) ms], [(97.42±44.86) ms vs (76.67±51.64) ms] were higher than those before march (n P0.05).n Conclusions:Long distance hiking will lead to acute injury of knee joint of young college students. The thickness of cartilage subregion of knee joint showed a thinning trend as a whole, while the volume and Tn 2 values showed different trends.n