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Objectives: The aim of this study was to introduce the MOCART 2.0 ankle score and evaluate its utility and reproducibility for the radiological assessment of cartilage repair tissue in the ankle joint. Methods: The MOCART 2.0 ankle score evaluates seven individual variables, including "volume fill of (osteo)chondral defect," "Integration into adjacent cartilage and bone," "surface of the repair tissue," "signal intensity of the repair tissue," "bony defect and bony overgrowth," "presence of edema-like-marrow signal," and "presence of subchondral cysts." Overall, a MOCART 2.0 ankle score between 0 and 100 points may be reached. Two independent readers assessed the 3-T MRI examinations of 48 ankles, who had undergone cartilage repair of a talar cartilage defect using the new MOCART 2.0 ankle score. One of the readers performed two readings. Intra- and interrater reliability were assessed using intraclass correlation coefficients (ICCs) for the overall MOCART 2.0 ankle score. Results: Forty-eight ankles (mean age at surgery 30.2 ± 11.2 years) were evaluated. The overall interrater (ICC = 0.75; 95%CI 0.60–0.85), as well as the intrarater (ICC = 0.83; 95%CI 0.72–0.90) reliability of the MOCART 2.0 ankle score was good. For individual variables the interrater reliability ranged from a kappa value of 0.29 (95%CI 0.01–0.57) for "surface of the repair tissue" to 0.83 (95%CI 0.71–0.95) for "presence of subchondral cysts". Conclusions: The newly introduced MOCART 2.0 ankle score, which encompasses the distinct anatomy of the ankle joint, demonstrates good intra- and interrater reliability. Critical relevance statement: The newly introduced MOCART 2.0 ankle score may facilitate the standardized assessment of cartilage repair in the ankle joint and allow an objective comparison of the morphological outcome between alternative treatment options and between different studies. Key Points: This study introduces the MOCART 2.0 ankle score. The MOCART 2.0 ankle score demonstrated good intra- and interrater reliability. Standardized reporting may improve communication between radiologists and other physicians. [ABSTRACT FROM AUTHOR]

Objectives: The aim of this study was to assess the texture of repair tissue and tissue adjacent to the repair site after matrix-associated chondrocyte transplantation (MACT) of the knee using gray-level co-occurrence matrix (GLCM) texture analysis of T2 quantitative maps. Methods: Twenty patients derived from the MRI sub-study of multicenter, single-arm phase III study underwent examination on a 3 T MR scanner, including a T2 mapping sequence 12 and 24 months after MACT. Changes between the time points in mean T2 values and 20 GLCM features were assessed for repair tissue, adjacent tissue, and reference cartilage. Differences in T2 values and selected GLCM features between the three cartilage sites at two time points were analyzed using linear mixed-effect models. Results: A significant decrease in T2 values after MACT, between time points, was observed only in repair cartilage (p < 0.001). Models showed significant differences in GLCM features between repair tissue and reference cartilage, namely, autocorrelation (p < 0.001), correlation (p = 0.015), homogeneity (p = 0.002), contrast (p < 0.001), and difference entropy (p = 0.047). The effect of time was significant in a majority of models with regard to GLCM features (except autocorrelation) (p ≤ 0.001). Values in repair and adjacent tissue became similar to reference tissue over time. Conclusions: GLCM is a useful add-on to T2 mapping in the evaluation of knee cartilage after MACT by increasing the sensitivity to changes in cartilage structure. The results suggest that cartilage tissue adjacent to the repair site heals along with the cartilage implant. Key Points: • GLCM is a useful add-on to T2mapping in the evaluation of knee cartilage after MACT by increasing the sensitivity to changes in cartilage structure. • Repair and adjacent tissue became similar to reference tissue over time. • The results suggest that cartilage tissue adjacent to the repair site heals along with the cartilage implant. [ABSTRACT FROM AUTHOR]

Objectives: This study evaluates GRAPPATINI, an accelerated T2 mapping sequence combining undersampling and model-based reconstruction to facilitate the clinical implementation of T2 mapping of the lumbar intervertebral disc. Methods: Fifty-eight individuals (26 females, 32 males, age 23.3 ± 8.0 years) were prospectively examined at 3 T. This cohort study consisted of 19 patients, 20 rowers, and 19 volunteers. GRAPPATINI was conducted with the same parameters as a conventional 2D multi-echo spin-echo (MESE) sequence in 02:27 min instead of 13:18 min. Additional T2 maps were calculated after discarding the first echo (T2-WO1ST) and only using even echoes (T2-EVEN). Segmentation was done on the four most central slices. The resulting T2 values were compared for all four measurements. Results: T2-GRAPPATINI, T2-MESE, T2-EVEN, and T2-WO1ST of the nucleus pulposus of normal discs differed significantly from those of bulging discs or herniated discs (all p < 0.001). For the posterior annular region, only T2-GRAPPATINI showed a significant difference (p = 0.011) between normal and herniated discs. There was a significant difference between T2-GRAPPATINI, T2-MESE, T2-EVEN, and T2-WO1ST of discs with and without an annular tear for the nucleus pulposus (all p < 0.001). The nucleus pulposus' T2 at different degeneration states showed significant differences between all group comparisons of Pfirrmann grades for T2-GRAPPATINI (p = 0.000–0.018), T2-MESE (p = 0.000–0.015), T2-EVEN (p = 0.000–0.019), and T2-WO1ST (p = 0.000–0.015). Conclusions: GRAPPATINI facilitates the use of T2 values as quantitative imaging biomarkers to detect disc pathologies such as degeneration, lumbar disc herniation, and annular tears while simultaneously shortening the acquisition time from 13:18 to 2:27 min. Key Points: • T2-GRAPPATINI, T2-MESE, T2-EVEN, and T2-WO1STof the nucleus pulposus of normal discs differed significantly from those of discs with bulging or herniation (all p < 0.001). • The investigated T2mapping techniques differed significantly in discs with and without annular tearing (all p < 0.001). • The nucleus pulposus' T2showed significant differences between different stages of degeneration in all group comparisons for T2-GRAPPATINI(p = 0.000–0.018), T2-MESE(p = 0.000–0.015), T2-EVEN(p = 0.000–0.019), and T2-WO1ST(p = 0.000–0.015). [ABSTRACT FROM AUTHOR]

Objectives: To assess the clinical relevance of T2 relaxation times, measured by 3D triple-echo steady-state (3D-TESS), in knee articular cartilage compared to conventional multi-echo spin-echo T2-mapping.Methods: Thirteen volunteers and ten patients with focal cartilage lesions were included in this prospective study. All subjects underwent 3-Tesla MRI consisting of a multi-echo multi-slice spin-echo sequence (CPMG) as a reference method for T2 mapping, and 3D TESS with the same geometry settings, but variable acquisition times: standard (TESSs 4:35min) and quick (TESSq 2:05min). T2 values were compared in six different regions in the femoral and tibial cartilage using a Wilcoxon signed ranks test and the Pearson correlation coefficient (r). The local ethics committee approved this study, and all participants gave written informed consent.Results: The mean quantitative T2 values measured by CPMG (mean: 46±9ms) in volunteers were significantly higher compared to those measured with TESS (mean: 31±5ms) in all regions. Both methods performed similarly in patients, but CPMG provided a slightly higher difference between lesions and native cartilage (CPMG: 90ms→61ms [31%],p=0.0125;TESS 32ms→24ms [24%],p=0.0839).Conclusions: 3D-TESS provides results similar to those of a conventional multi-echo spin-echo sequence with many benefits, such as shortening of total acquisition time and insensitivity to B1 and B0 changes.Key Points: • 3D-TESS T 2 mapping provides clinically comparable results to CPMG in shorter scan-time. • Clinical and investigational studies may benefit from high temporal resolution of 3D-TESS. • 3D-TESS T 2 values are able to differentiate between healthy and damaged cartilage. [ABSTRACT FROM AUTHOR]

Objective: To evaluate the feasibility of in vivo (23)Na imaging of the corticomedullary (23)Na gradient and to measure (23)Na transverse relaxation times (T2*) in human kidneys.Methods: In this prospective, IRB-approved study, eight healthy volunteers (4 female, 4 male; mean age 29.4 ± 3.6 years) were examined on a 7-T whole-body MR system using a (23)Na-only spine-array coil. For morphological (23)Na-MRI, a 3D gradient echo (GRE) sequence with a variable echo time scheme (vTE) was used. T2* times were calculated using a multiecho 3D vTE-GRE approach. (23)Na signal-to-noise ratios (SNR) were given on a pixel-by-pixel basis for a 20-mm section from the cortex in the direction of the medulla. T2* maps were calculated by fitting the (23)Na signal decay monoexponentially on a pixel-by-pixel basis, using least squares fit.Results: Mean corticomedullary (23)Na-SNR increased from the cortex (32.2 ± 5.6) towards the medulla (85.7 ± 16.0). The SNR increase ranged interindividually from 57.2% to 66.3%. Mean (23)Na-T2* relaxation times differed statistically significantly (P < 0.001) between the cortex (17.9 ± 0.8 ms) and medulla (20.6 ± 1.0 ms).Conclusion: The aim of this study was to evaluate the feasibility of in vivo (23)Na MRI of the corticomedullary (23)Na gradient and to measure the (23)Na T2* relaxation times of human kidneys at 7 T.Key Points: • High field MR offers new insights into renal anatomy and physiology. • (23) Na MRI of healthy human kidneys is feasible at ultra-high field. • Renal (23) Na concentration increases from the cortex in the medullary pyramid direction. • In vivo measurements of renal (23) Na-T2* times are demonstrated at 7.0 T. [ABSTRACT FROM AUTHOR]

Objective: To evaluate the feasibility of in vivo Na imaging of the corticomedullary Na gradient and to measure Na transverse relaxation times (T2*) in human kidneys. Methods: In this prospective, IRB-approved study, eight healthy volunteers (4 female, 4 male; mean age 29.4 ± 3.6 years) were examined on a 7-T whole-body MR system using a Na-only spine-array coil. For morphological Na-MRI, a 3D gradient echo (GRE) sequence with a variable echo time scheme (vTE) was used. T2* times were calculated using a multiecho 3D vTE-GRE approach. Na signal-to-noise ratios (SNR) were given on a pixel-by-pixel basis for a 20-mm section from the cortex in the direction of the medulla. T2* maps were calculated by fitting the Na signal decay monoexponentially on a pixel-by-pixel basis, using least squares fit. Results: Mean corticomedullary Na-SNR increased from the cortex (32.2 ± 5.6) towards the medulla (85.7 ± 16.0). The SNR increase ranged interindividually from 57.2 % to 66.3 %. Mean Na-T2* relaxation times differed statistically significantly ( P < 0.001) between the cortex (17.9 ± 0.8 ms) and medulla (20.6 ± 1.0 ms). Conclusion: The aim of this study was to evaluate the feasibility of in vivo Na MRI of the corticomedullary Na gradient and to measure the Na T2* relaxation times of human kidneys at 7 T. Key Points: • High field MR offers new insights into renal anatomy and physiology. • Na MRI of healthy human kidneys is feasible at ultra- high field. • Renal Na concentration increases from the cortex in the medullary pyramid direction. • In vivo measurements of renal Na- T2* times are demonstrated at 7. 0 T. [ABSTRACT FROM AUTHOR]

Objective: To compare mono- and bi-exponential T2 analysis in healthy and degenerated Achilles tendons using a recently introduced magnetic resonance variable-echo-time sequence (vTE) for T2 mapping.Methods: Ten volunteers and ten patients were included in the study. A variable-echo-time sequence was used with 20 echo times. Images were post-processed with both techniques, mono- and bi-exponential [T2 m, short T2 component (T2 s) and long T2 component (T2 l)]. The number of mono- and bi-exponentially decaying pixels in each region of interest was expressed as a ratio (B/M). Patients were clinically assessed with the Achilles Tendon Rupture Score (ATRS), and these values were correlated with the T2 values.Results: The means for both T2 m and T2 s were statistically significantly different between patients and volunteers; however, for T2 s, the P value was lower. In patients, the Pearson correlation coefficient between ATRS and T2 s was -0.816 (P = 0.007).Conclusion: The proposed variable-echo-time sequence can be successfully used as an alternative method to UTE sequences with some added benefits, such as a short imaging time along with relatively high resolution and minimised blurring artefacts, and minimised susceptibility artefacts and chemical shift artefacts. Bi-exponential T2 calculation is superior to mono-exponential in terms of statistical significance for the diagnosis of Achilles tendinopathy.Key Points: • Magnetic resonance imaging offers new insight into healthy and diseased Achilles tendons • Bi-exponential T2 calculation in Achilles tendons is more beneficial than mono-exponential • A short T2 component correlates strongly with clinical score • Variable echo time sequences successfully used instead of ultrashort echo time sequences. [ABSTRACT FROM AUTHOR]

Objectives: This article provides an overview of the initial clinical results of musculoskeletal studies performed at 7 Tesla, with special focus on sodium imaging, new techniques such as chemical exchange saturation transfer (CEST) and T2* imaging, and multinuclear MR spectroscopy.Methods: Sodium imaging was clinically used at 7 T in the evaluation of patients after cartilage repair procedures because it enables the GAG content to be monitored over time. Sodium imaging and T2* mapping allow insights into the ultra-structural composition of the Achilles tendon and help detect early disease. Chemical exchange saturation transfer was, for the first time, successfully applied in the clinical set-up at 7 T in patients after cartilage repair surgery. The potential of phosphorus MR spectroscopy in muscle was demonstrated in a comparison study between 3 and 7 T, with higher spectral resolution and significantly shorter data acquisition times at 7 T.Results: These initial clinical studies demonstrate the potential of ultra-high field MR at 7 T, with the advantage of significantly improved sensitivity for other nuclei, such as (23)Na (sodium) and (31)P (phosphorus).Conclusions: The application of non-proton imaging and spectroscopy provides new insights into normal and abnormal physiology of musculoskeletal tissues, particularly cartilage, tendons, and muscles.Key Points: • 7 T magnetic resonance provides significantly improved sensitivity for ( 23 ) Na and ( 31 ) P. • Initial clinical studies have now demonstrated ultra-high field MR operating at 7 T. • 7 T provides new insights into normal and abnormal physiology of musculoskeletal tissues. [ABSTRACT FROM AUTHOR]

Objectives: To show the feasibility and possible superiority of two 7 Tesla knee protocols ('7 T high resolution' and '7 T quick') using a new 28-channel knee coil compared to an optimised 3 T knee protocol using an 8-channel knee coil. Methods: The study was approved by the ethics committee. Both 3 T and 7 T MRI of the knee were performed in 10 healthy volunteers (29.6 ± 7.9 years), with two 2D sequences (PD-TSE and T1-SE) and three isotropic 3D sequences (TRUFI, FLASH and PD-TSE SPACE). Quantitative contrast-to-noise ratio (CNR) and qualitative evaluations were performed by different readers, and intra- and inter-rater agreement was assessed. Results: The signal-to-noise ratio (SNR) as well as the CNR values for cartilage-bone, cartilage-fluid, cartilage-menisci and menisci-fluid were, in most cases, higher at 7 T compared to 3 T, and the 7 T quick measurement was slightly superior compared to the 7 T high-resolution measurement. The results of the subjective qualitative analysis were higher for the 7 T measurements compared to the 3 T measurements. Inter- and intra-observer reliability was high (0.884-0.999). Conclusions: Through higher field strength and an optimal coil, resolution at 7 T can be increased and acquisition time can be reduced, with superior quantitative and comparable qualitative results compared to 3 T. Key Points: • 7-Tesla MRI using a dedicated 28-channel knee coil provides high quality. • Isotropic 3D-MR sequences benefit more from ultra-high-field than basic 2D sequences. • At 7 T high resolution and short MR acquisition are possible. • Dedicated coils ensure the clinical applicability of musculoskeletal MRI at ultra-high-field. [ABSTRACT FROM AUTHOR]

The aims of this study were to examine the clinical feasibility and reproducibility of kinematic MR imaging with respect to changes in T (2) in the femoral condyle articular cartilage. We used a flexible knee coil, which allows acquisition of data in different positions from 40 degrees flexion to full extension during MR examinations. The reproducibility of T (2) measurements was evaluated for inter-rater and inter-individual variability and determined as a coefficient of variation (CV) for each volunteer and rater. Three different volunteers were measured twice and regions of interest (ROIs) were selected by three raters at different time points. To prove the clinical feasibility of this method, 20 subjects (10 patients and 10 age- and sex-matched volunteers) were enrolled in the study. Inter-rater variability ranged from 2 to 9 and from 2 to 10% in the deep and superficial zones, respectively. Mean inter-individual variability was 7% for both zones. Different T (2) values were observed in the superficial cartilage zone of patients compared with volunteers. Since repair tissue showed a different behavior in the contact zone compared with healthy cartilage, a possible marker for improved evaluation of repair tissue quality after matrix-associated autologous chondrocyte transplantation (MACT) may be available and may allow biomechanical assessment of cartilage transplants. [ABSTRACT FROM AUTHOR]

Objectives: Bone marrow edema-like signal (BMELS) after cartilage repair is common, but its clinical significance remains uncertain. This study aimed to investigate the clinical and structural significance of BMELS following microfracturing (MFX) and matrix-induced autologous chondrocyte implantation (MACI).In this multicenter study, MRI examinations were performed over a period of 5 years after cartilage repair surgery (MFX n = 17; MACI n = 28) in 45 patients. Morphological assessments, including the MOCART 2.0 (magnetic resonance observation of cartilage repair tissue), quantitative imaging biomarkers (QIB) with T2 mapping of the repair tissue, and, specifically, assessment of the presence and size of BMELS, were conducted along with patient-reported outcome measures, such as the Knee injury and Osteoarthritis Outcome Score (KOOS) and the International Knee Documentation Committee (IKDC). BMELS structural and clinical assessments were obtained after 3 months, 12 months, and 60 months. Statistical analysis included the Mann–Whitney U-test, Wilcoxon rank test, Shapiro–Wilk test, and simulation-based power analysis.BMELS were a common finding 60 months after cartilage repair. The size of BMELS differed significantly only between MACI and MFX patients after 3 months, with larger BMELS occurring in the MFX group. There were no significant differences in patients with or without BMELS regarding the T2 ratio of the treated area, the MOCART 2.0, or clinical scores.BMELS frequently appeared after cartilage repair procedures. We could show that the postoperative size and change in the size of BMELS after MACI and MFX did not affect clinical scores, morphological MRI results, or biochemical properties of the treated area after 60 months.QuestionWhat is the clinical significance of bone marrow edema-like signal (BMELS) appearance after matrix-induced autologous chondrocyte implantation (MACI) or microfracture (MFX)?FindingThere were no significant differences in patients with or without BMELS regarding the T2 ratio of the treated area, the MOCART 2.0, or clinical scores.Clinical relevanceBMELS frequently appeared after cartilage repair, the appearance or the size dynamic after MACI and MFX did not affect clinical scores, morphological MRI results, or biochemical properties after 60 months.Methods: Bone marrow edema-like signal (BMELS) after cartilage repair is common, but its clinical significance remains uncertain. This study aimed to investigate the clinical and structural significance of BMELS following microfracturing (MFX) and matrix-induced autologous chondrocyte implantation (MACI).In this multicenter study, MRI examinations were performed over a period of 5 years after cartilage repair surgery (MFX n = 17; MACI n = 28) in 45 patients. Morphological assessments, including the MOCART 2.0 (magnetic resonance observation of cartilage repair tissue), quantitative imaging biomarkers (QIB) with T2 mapping of the repair tissue, and, specifically, assessment of the presence and size of BMELS, were conducted along with patient-reported outcome measures, such as the Knee injury and Osteoarthritis Outcome Score (KOOS) and the International Knee Documentation Committee (IKDC). BMELS structural and clinical assessments were obtained after 3 months, 12 months, and 60 months. Statistical analysis included the Mann–Whitney U-test, Wilcoxon rank test, Shapiro–Wilk test, and simulation-based power analysis.BMELS were a common finding 60 months after cartilage repair. The size of BMELS differed significantly only between MACI and MFX patients after 3 months, with larger BMELS occurring in the MFX group. There were no significant differences in patients with or without BMELS regarding the T2 ratio of the treated area, the MOCART 2.0, or clinical scores.BMELS frequently appeared after cartilage repair procedures. We could show that the postoperative size and change in the size of BMELS after MACI and MFX did not affect clinical scores, morphological MRI results, or biochemical properties of the treated area after 60 months.QuestionWhat is the clinical significance of bone marrow edema-like signal (BMELS) appearance after matrix-induced autologous chondrocyte implantation (MACI) or microfracture (MFX)?FindingThere were no significant differences in patients with or without BMELS regarding the T2 ratio of the treated area, the MOCART 2.0, or clinical scores.Clinical relevanceBMELS frequently appeared after cartilage repair, the appearance or the size dynamic after MACI and MFX did not affect clinical scores, morphological MRI results, or biochemical properties after 60 months.Results: Bone marrow edema-like signal (BMELS) after cartilage repair is common, but its clinical significance remains uncertain. This study aimed to investigate the clinical and structural significance of BMELS following microfracturing (MFX) and matrix-induced autologous chondrocyte implantation (MACI).In this multicenter study, MRI examinations were performed over a period of 5 years after cartilage repair surgery (MFX n = 17; MACI n = 28) in 45 patients. Morphological assessments, including the MOCART 2.0 (magnetic resonance observation of cartilage repair tissue), quantitative imaging biomarkers (QIB) with T2 mapping of the repair tissue, and, specifically, assessment of the presence and size of BMELS, were conducted along with patient-reported outcome measures, such as the Knee injury and Osteoarthritis Outcome Score (KOOS) and the International Knee Documentation Committee (IKDC). BMELS structural and clinical assessments were obtained after 3 months, 12 months, and 60 months. Statistical analysis included the Mann–Whitney U-test, Wilcoxon rank test, Shapiro–Wilk test, and simulation-based power analysis.BMELS were a common finding 60 months after cartilage repair. The size of BMELS differed significantly only between MACI and MFX patients after 3 months, with larger BMELS occurring in the MFX group. There were no significant differences in patients with or without BMELS regarding the T2 ratio of the treated area, the MOCART 2.0, or clinical scores.BMELS frequently appeared after cartilage repair procedures. We could show that the postoperative size and change in the size of BMELS after MACI and MFX did not affect clinical scores, morphological MRI results, or biochemical properties of the treated area after 60 months.QuestionWhat is the clinical significance of bone marrow edema-like signal (BMELS) appearance after matrix-induced autologous chondrocyte implantation (MACI) or microfracture (MFX)?FindingThere were no significant differences in patients with or without BMELS regarding the T2 ratio of the treated area, the MOCART 2.0, or clinical scores.Clinical relevanceBMELS frequently appeared after cartilage repair, the appearance or the size dynamic after MACI and MFX did not affect clinical scores, morphological MRI results, or biochemical properties after 60 months.Conclusion: Bone marrow edema-like signal (BMELS) after cartilage repair is common, but its clinical significance remains uncertain. This study aimed to investigate the clinical and structural significance of BMELS following microfracturing (MFX) and matrix-induced autologous chondrocyte implantation (MACI).In this multicenter study, MRI examinations were performed over a period of 5 years after cartilage repair surgery (MFX n = 17; MACI n = 28) in 45 patients. Morphological assessments, including the MOCART 2.0 (magnetic resonance observation of cartilage repair tissue), quantitative imaging biomarkers (QIB) with T2 mapping of the repair tissue, and, specifically, assessment of the presence and size of BMELS, were conducted along with patient-reported outcome measures, such as the Knee injury and Osteoarthritis Outcome Score (KOOS) and the International Knee Documentation Committee (IKDC). BMELS structural and clinical assessments were obtained after 3 months, 12 months, and 60 months. Statistical analysis included the Mann–Whitney U-test, Wilcoxon rank test, Shapiro–Wilk test, and simulation-based power analysis.BMELS were a common finding 60 months after cartilage repair. The size of BMELS differed significantly only between MACI and MFX patients after 3 months, with larger BMELS occurring in the MFX group. There were no significant differences in patients with or without BMELS regarding the T2 ratio of the treated area, the MOCART 2.0, or clinical scores.BMELS frequently appeared after cartilage repair procedures. We could show that the postoperative size and change in the size of BMELS after MACI and MFX did not affect clinical scores, morphological MRI results, or biochemical properties of the treated area after 60 months.QuestionWhat is the clinical significance of bone marrow edema-like signal (BMELS) appearance after matrix-induced autologous chondrocyte implantation (MACI) or microfracture (MFX)?FindingThere were no significant differences in patients with or without BMELS regarding the T2 ratio of the treated area, the MOCART 2.0, or clinical scores.Clinical relevanceBMELS frequently appeared after cartilage repair, the appearance or the size dynamic after MACI and MFX did not affect clinical scores, morphological MRI results, or biochemical properties after 60 months.Key Points: Bone marrow edema-like signal (BMELS) after cartilage repair is common, but its clinical significance remains uncertain. This study aimed to investigate the clinical and structural significance of BMELS following microfracturing (MFX) and matrix-induced autologous chondrocyte implantation (MACI).In this multicenter study, MRI examinations were performed over a period of 5 years after cartilage repair surgery (MFX n = 17; MACI n = 28) in 45 patients. Morphological assessments, including the MOCART 2.0 (magnetic resonance observation of cartilage repair tissue), quantitative imaging biomarkers (QIB) with T2 mapping of the repair tissue, and, specifically, assessment of the presence and size of BMELS, were conducted along with patient-reported outcome measures, such as the Knee injury and Osteoarthritis Outcome Score (KOOS) and the International Knee Documentation Committee (IKDC). BMELS structural and clinical assessments were obtained after 3 months, 12 months, and 60 months. Statistical analysis included the Mann–Whitney U-test, Wilcoxon rank test, Shapiro–Wilk test, and simulation-based power analysis.BMELS were a common finding 60 months after cartilage repair. The size of BMELS differed significantly only between MACI and MFX patients after 3 months, with larger BMELS occurring in the MFX group. There were no significant differences in patients with or without BMELS regarding the T2 ratio of the treated area, the MOCART 2.0, or clinical scores.BMELS frequently appeared after cartilage repair procedures. We could show that the postoperative size and change in the size of BMELS after MACI and MFX did not affect clinical scores, morphological MRI results, or biochemical properties of the treated area after 60 months.QuestionWhat is the clinical significance of bone marrow edema-like signal (BMELS) appearance after matrix-induced autologous chondrocyte implantation (MACI) or microfracture (MFX)?FindingThere were no significant differences in patients with or without BMELS regarding the T2 ratio of the treated area, the MOCART 2.0, or clinical scores.Clinical relevanceBMELS frequently appeared after cartilage repair, the appearance or the size dynamic after MACI and MFX did not affect clinical scores, morphological MRI results, or biochemical properties after 60 months. [ABSTRACT FROM AUTHOR]

The purpose of this study was to investigate potential changes in the anterior cruciate ligament (ACL) structure of alpine ski racers over the course of an entire season using quantitative magnetic resonance imaging (T2* mapping). The dominant legs of three alpine ski racers were examined on a 3-T MR scanner four times at 3-month intervals. Multi-echo sequences for T2* maps, which were coregistered with high-resolution morphological sequences for reproducible definition of ACL regions of interest, were acquired. Means and standard deviations of T2* values from the central and femoral portion of the ACL were extracted and presented in a descriptive manner. T2* values were subject to seasonal changes, which were most pronounced in the ligament central region. Substantial increases (+ 41%) occurred between the measurements taken in January and April. A partial recovery of T2* (-19%) was observed in the July follow-up. The increased T2* times may reflect decreased stress tolerance and increased susceptibility for fatigue tears at the end of the competitive season. Further research in larger samples is required. The likeliness of ACL tears may depend on the precedent history of mechanical loading and vary in professional athletes over the course of the competitive season. [ABSTRACT FROM AUTHOR]