{"doi":"10.1002/mrm.29930","title":"Changes in tissue sodium concentration and sodium relaxation times during the maturation of human knee cartilage: Ex vivo <scp><sup>23</sup>Na MRI</scp> study at 10.<scp>5 T</scp>","abstract":"Abstract Purpose To evaluate the influence of skeletal maturation on sodium ( 23 Na) MRI relaxation parameters and the accuracy of tissue sodium concentration (TSC) quantification in human knee cartilage. Methods Twelve pediatric knee specimens were imaged with whole‐body 10.5 T MRI using a density‐adapted 3D radial projection sequence to evaluate 23 Na parameters: B 1 + , T 1 , biexponential , and TSC. Water, collagen, and sulfated glycosaminoglycan (sGAG) content were calculated from osteochondral biopsies. The TSC was corrected for B 1 + , relaxation, and water content. The literature‐based TSC (TSC LB ) used previously published values for corrections, whereas the specimen‐specific TSC (TSC SP ) used measurements from individual specimens. 23 Na parameters were evaluated in eight cartilage compartments segmented on proton images. Associations between 23 Na parameters, TSC LB − TSC SP difference, biochemical content, and age were determined. Results From birth to 12 years, cartilage water content decreased by 18%; collagen increased by 59%; and sGAG decreased by 36% (all R 2 ≥ 0.557). The short () decreased by 72%, and the signal fraction relaxing with () increased by 55% during the first 5 years but remained relatively stable after that. TSC SP was significantly correlated with sGAG content from biopsies ( R 2 = 0.739). Depending on age, TSC LB showed higher or lower values than TSC SP . The TSC LB − TSC SP difference was significantly correlated with ( R 2 = 0.850), ( R 2 = 0.651), and water content ( R 2 = 0.738). Conclusion TSC and relaxation parameters measured with 23 Na MRI provide noninvasive information about changes in sGAG content and collagen matrix during cartilage maturation. Cartilage TSC quantification assuming fixed relaxation may be feasible in children older than 5 years.","journal":"Magnetic Resonance in Medicine","year":2023,"id":354447,"datarank":0.0,"base_score":0.0,"endowment":0.0,"self_citation_contribution":0.0,"citation_network_contribution":0.0,"self_endowment_contribution":0.0,"citer_contribution":0.0,"corpus_percentile":null,"corpus_rank":null,"citation_count":7,"citer_count":0,"citers_with_citation_signal":0,"citers_with_endowment":0,"datacite_reuse_total":0,"is_dataset":false,"is_dataset_confidence":0.6776,"is_data_producer":false,"deposit_databanks":null,"is_oa":true,"file_count":0,"downloads":0,"has_version_chain":false,"published_date":"2023-01-01","fair_score":null,"fair_percentile":null,"algorithm_id":"datarank_citation_only_1hop_v6","ranking_scope":"data_only","authors":[{"id":428940,"name":"Kai D. Ludwig","orcid":"0000-0001-9867-9346","position":1,"is_corresponding":false},{"id":426368,"name":"Lauren Watkins","orcid":"0000-0003-3592-4089","position":2,"is_corresponding":false},{"id":320267,"name":"Russell Lagore","orcid":"0000-0003-1950-1828","position":3,"is_corresponding":false},{"id":1102015,"name":"Amanda Nowacki","orcid":null,"position":4,"is_corresponding":false},{"id":628227,"name":"Ferenc Tóth","orcid":"0000-0002-6615-389X","position":5,"is_corresponding":false},{"id":428947,"name":"Marc Tompkins","orcid":"0000-0002-8641-3150","position":6,"is_corresponding":false},{"id":1101612,"name":"Lin Zhang","orcid":"0000-0001-5684-2555","position":7,"is_corresponding":false},{"id":320269,"name":"Gregor Adriany","orcid":"0000-0002-6428-9005","position":8,"is_corresponding":false},{"id":249604,"name":"Garry E. Gold","orcid":"0000-0002-3207-822X","position":9,"is_corresponding":false},{"id":481265,"name":"Kevin G. Shea","orcid":"0000-0002-4160-0163","position":10,"is_corresponding":false},{"id":407455,"name":"Armin M. Nagel","orcid":"0000-0003-0948-1421","position":11,"is_corresponding":false},{"id":429604,"name":"Cathy S. Carlson","orcid":null,"position":12,"is_corresponding":false},{"id":393368,"name":"Gregory J. Metzger","orcid":"0000-0002-3187-6529","position":13,"is_corresponding":false},{"id":399491,"name":"Jutta Ellermann","orcid":"0000-0002-7109-9656","position":14,"is_corresponding":false},{"id":428941,"name":"Štefan Zbýň","orcid":"0000-0002-8211-2828","position":0,"is_corresponding":true}],"reference_count":66,"raw_metadata":null,"created_at":"2026-07-19T01:13:06.959762Z","pmid":"37997011","pmcid":null,"fwci":null,"citation_percentile":null,"influential_citations":0,"oa_status":null,"license":null,"views":0,"total_file_size_bytes":0,"version_count":0,"fair_f":null,"fair_a":null,"fair_i":null,"fair_r":null,"fair_zscore":null,"fair_rationale":null,"fair_model":null,"fair_agent_version":null,"fair_fulltext_source":null,"fair_has_llm":null,"fair_computed_at":null,"clinical_trials":[],"software_tools":[],"db_accessions":[],"linked_datasets":[],"topics":[]}