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- Detection of physiological changes in knee cartilage using parametric T2 relaxation maps estimated with a dictionary methodPublication . Coelho, José M.; Fernandes, Tiago T.; Alves, Sandra M.; Vilaça, Adélio; Nunes, Rita G.; Nogueira, Luísa; Oliveira, António; Nogueira, Luisa; Alves, Sandra MariaTo investigate half-marathon running and recovery effects on knee articular cartilage (KAC) health in athletes, using dictionary-matching T2 maps, to detect changes and recovery patterns in KAC. Eleven asymptomatic volunteers (4 females, 7 males; mean age 40 ± 5 years, mean BMI 22.7 ± 1.4 kg/m2) completed a fixed-pace half-marathonwere studied. All were right-knee dominant and engaged in regular running. Sagittal T2-weighted Multi-Echo Spin-Echo images at 3 T were used to assess T2 values pre-run, post-run, and one week later for global and compartmental KAC. Recovery programme included low-intensity running, strength training and rest. Repeated measures ANOVA or equivalent non-parametric tests with post-hoc comparisons compared T2 values over time. Separate analyses were conducted based on laterality, gender and anatomical compartments. Significance was set at < 0.05. Post-run T2 values decreased significantly by 0.9 ms (− 2.0%, p < 0.001), with up to 5.3% reductions in medial tibial (MT) and femoral (MF) compartments. Recovery patterns varied by compartment, sex and laterality. Most compartments returned to baseline within one week; the lateral condyle (LatC) showed incomplete recovery (− 4.7%, Proportional Recovery Index (PRI) = − 0,1); the right knee’s MT exhibited overcompensation (6.3%, PRI = 2.6). Males showed higher baseline T2 values and more efficient recovery in the LatC compared to females (PRI = − 0.1 vs. − 0.4). Half-marathon running induces reversible reductions in KAC hydration, with most compartments recovering or overcompensating within one week. Dictionary-matching T2 mapping offers a robust approach for monitoring cartilage integrity and guiding individualised recovery strategies.
- Impact of walking on knee articular cartilage T2 values estimated with a dictionary-based approach - A pilot studyPublication . Coelho, José M.; Fernandes, T.T.; Alves, Sandra Maria; Nunes, R.G.; Nogueira, Luísa; Oliveira, A.Walking is crucial for knee articular cartilage (KAC) health. Routine MRI sequences lack sensitivity for early cartilage changes, and the use of parametric T2 maps to study the effect of walking on KAC composition is limited. This study aimed to evaluate if quantitative T2 maps using an Echo Modulation Curve (EMC) matching algorithm can detect KAC T2 variations due to water content changes after walking. Seven asymptomatic volunteers (3 females, 4 males, mean age 28.3 years) without knee pathologies participated. Sagittal knee MRI scans were performed before and after a 9-min treadmill walk using a Modified Bruce protocol. T2-weighted Multi-Echo Spin-Echo KAC images were acquired at 3T. Tibiofemoral cartilage was segmented semi-automatically on three slices per knee, defining 39 KAC samples. Quantitative T2 maps were created using a dictionary-matching algorithm. Paired t-tests assessed exercise impact on KAC T2 values, independent t-tests compared group differences, and Friedman test with Bonferroni correction evaluated regional T2 changes. Walking increased KAC T2 values (mean difference (md) 0.61 ± 1.71 ms; p ¼ 0.016). Significant differences were observed in “normal” BMI group (md 0.69 ± 1.27 ms; p ¼ 0.021). Regional analysis revealed significant differences in medial femur in males (md 0.9 ± 2.1 ms; p ¼ 0.049) and lateral tibia in females (md 1.4 ± 2.5 ms; p ¼ 0.046). The medial tibia showed significant differences across sub-regions (p ¼ 0.026). Quantitative T2 maps using the EMC matching algorithm detected consistent changes in KAC T2 values after a short walking period. Implications for practice: EMC quantitative T2 maps effectively detected knee cartilage changes postwalking. This technique could improve cartilage hydration assessments, aiding early detection in atrisk patients. It also suggests potential for personalized monitoring and rehabilitation, advancing musculoskeletal imaging and non-invasive joint health monitoring.