{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,6,26]],"date-time":"2026-06-26T06:14:01Z","timestamp":1782454441420,"version":"3.54.5"},"reference-count":13,"publisher":"Wiley","issue":"2","license":[{"start":{"date-parts":[[2025,11,2]],"date-time":"2025-11-02T00:00:00Z","timestamp":1762041600000},"content-version":"vor","delay-in-days":0,"URL":"http:\/\/onlinelibrary.wiley.com\/termsAndConditions#vor"}],"funder":[{"DOI":"10.13039\/100000062","name":"National Institute of Diabetes and Digestive and Kidney Diseases","doi-asserted-by":"publisher","award":["1RO1DK097115\u201001A1"],"award-info":[{"award-number":["1RO1DK097115\u201001A1"]}],"id":[{"id":"10.13039\/100000062","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/100000097","name":"National Center for Research Resources","doi-asserted-by":"publisher","award":["UL1TR001855\u201002"],"award-info":[{"award-number":["UL1TR001855\u201002"]}],"id":[{"id":"10.13039\/100000097","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/100000065","name":"National Institute of Neurological Disorders and Stroke","doi-asserted-by":"publisher","award":["1R01NS117430\u201001A1"],"award-info":[{"award-number":["1R01NS117430\u201001A1"]}],"id":[{"id":"10.13039\/100000065","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":["onlinelibrary.wiley.com"],"crossmark-restriction":true},"short-container-title":["Magnetic Resonance in Med"],"published-print":{"date-parts":[[2026,2]]},"abstract":"Abstract<\/jats:title>\n \n Purpose<\/jats:title>\n \n The principles of signal\u2010intensity\u2010ratio (SIR) estimation were revisited to derive a set of generalizable equations to quantify liver iron concentration (LIC), extending the effective dynamic range of LIC\u2010R\n 2<\/jats:sub>\n * estimation or detect when LIC\u2010 R\n 2<\/jats:sub>\n * estimation degenerates.\n <\/jats:p>\n <\/jats:sec>\n \n Theory and Methods<\/jats:title>\n Equations for LIC were derived for two techniques: (1) relaxometry of multi\u2010echo gradient echo and (2) SIR of liver and muscle tissue in a single echo. MRI was completed at 1.5T and 3T in human subjects with a range of liver iron burdens. LIC was estimated by both techniques and compared to assess concordance across the clinical range and high LIC performance.<\/jats:p>\n <\/jats:sec>\n \n Results<\/jats:title>\n \n Regression of Log(\n SIR<\/jats:styled-content>\n ) by\n LIC<\/jats:styled-content>\n was linear for both 1.\n 5T<\/jats:styled-content>\n and\n 3T<\/jats:styled-content>\n data with similar slopes. Comparison between\n SIR<\/jats:styled-content>\n \u2010\n LIC<\/jats:styled-content>\n and R\n 2<\/jats:sub>\n *\u2010\n LIC<\/jats:styled-content>\n estimates demonstrated linear concordance until the echo time\u2013based saturation of R\n 2<\/jats:sub>\n * estimates were reached, at which point\n SIR<\/jats:styled-content>\n \u2010\n LIC<\/jats:styled-content>\n estimates continued to rise without a concomitant increase in R\n 2<\/jats:sub>\n *\u2010\n LIC<\/jats:styled-content>\n . Lack of spatial intensity correction caused systematic bias and increased variance in\n LIC<\/jats:styled-content>\n estimates compared to intensity\u2010corrected images.\n <\/jats:p>\n <\/jats:sec>\n \n Conclusions<\/jats:title>\n \n LIC\u2010SIR measurements can potentially be used to estimate liver iron concentration in examinations where R\n 2<\/jats:sub>\n * acquisitions were not performed or where the dynamic range of a multi\u2010echo protocol is exceeded. Using spatial intensity correction where possible improves SIR\u2010LIC estimates.\n <\/jats:p>\n <\/jats:sec>","DOI":"10.1002\/mrm.70078","type":"journal-article","created":{"date-parts":[[2025,11,3]],"date-time":"2025-11-03T04:41:58Z","timestamp":1762144918000},"page":"706-713","update-policy":"https:\/\/doi.org\/10.1002\/crossmark_policy","source":"Crossref","is-referenced-by-count":1,"title":["Revisiting signal intensity ratios for extending the dynamic range for iron overload estimation"],"prefix":"10.1002","volume":"95","author":[{"given":"Eamon K.","family":"Doyle","sequence":"first","affiliation":[{"name":"Department of Radiology Children's Hospital Los Angeles Los Angeles California USA"},{"name":"Department of Pediatrics, Keck School of Medicine University of Southern California Los Angeles California USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0009-0002-0008-4083","authenticated-orcid":false,"given":"Obdulio","family":"Carreras","sequence":"additional","affiliation":[{"name":"Children's Hospital Los Angeles Los Angeles California USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"John C.","family":"Wood","sequence":"additional","affiliation":[{"name":"Department of Pediatrics, Keck School of Medicine University of Southern California Los Angeles California USA"},{"name":"Department of Pediatrics, Division of Pediatric Cardiology Children's Hospital Los Angeles Los Angeles California USA"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"311","published-online":{"date-parts":[[2025,11,2]]},"reference":[{"key":"e_1_2_8_2_1","doi-asserted-by":"publisher","DOI":"10.1016\/j.mri.2015.02.016"},{"key":"e_1_2_8_3_1","doi-asserted-by":"publisher","DOI":"10.1111\/bjh.13374"},{"key":"e_1_2_8_4_1","doi-asserted-by":"publisher","DOI":"10.1002\/mrm.25459"},{"key":"e_1_2_8_5_1","doi-asserted-by":"publisher","DOI":"10.1002\/mrm.26791"},{"key":"e_1_2_8_6_1","doi-asserted-by":"publisher","DOI":"10.1002\/mrm.26592"},{"key":"e_1_2_8_7_1","doi-asserted-by":"publisher","DOI":"10.1016\/S0730-725X(03)00080-8"},{"key":"e_1_2_8_8_1","doi-asserted-by":"publisher","DOI":"10.1002\/mrm.28943"},{"key":"e_1_2_8_9_1","doi-asserted-by":"publisher","DOI":"10.1016\/S0140-6736(04)15436-6"},{"key":"e_1_2_8_10_1","first-page":"32","article-title":"Improved R2* measurements in myocardial iron overload","volume":"7","author":"Ghugre N","year":"2005","journal-title":"J Cardiovasc Magn Reson."},{"key":"e_1_2_8_11_1","doi-asserted-by":"publisher","DOI":"10.1002\/jmri.27928"},{"key":"e_1_2_8_12_1","doi-asserted-by":"publisher","DOI":"10.1016\/j.mri.2013.05.005"},{"key":"e_1_2_8_13_1","doi-asserted-by":"publisher","DOI":"10.1182\/blood-2004-10-3982"},{"key":"e_1_2_8_14_1","doi-asserted-by":"publisher","DOI":"10.1148\/radiol.213256"}],"container-title":["Magnetic Resonance in Medicine"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/onlinelibrary.wiley.com\/doi\/pdf\/10.1002\/mrm.70078","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,12,6]],"date-time":"2025-12-06T17:48:26Z","timestamp":1765043306000},"score":1,"resource":{"primary":{"URL":"https:\/\/onlinelibrary.wiley.com\/doi\/10.1002\/mrm.70078"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2025,11,2]]},"references-count":13,"journal-issue":{"issue":"2","published-print":{"date-parts":[[2026,2]]}},"alternative-id":["10.1002\/mrm.70078"],"URL":"https:\/\/doi.org\/10.1002\/mrm.70078","archive":["Portico"],"relation":{},"ISSN":["0740-3194","1522-2594"],"issn-type":[{"value":"0740-3194","type":"print"},{"value":"1522-2594","type":"electronic"}],"subject":[],"published":{"date-parts":[[2025,11,2]]},"assertion":[{"value":"2025-01-28","order":0,"name":"received","label":"Received","group":{"name":"publication_history","label":"Publication History"}},{"value":"2025-08-26","order":2,"name":"accepted","label":"Accepted","group":{"name":"publication_history","label":"Publication History"}},{"value":"2025-11-02","order":3,"name":"published","label":"Published","group":{"name":"publication_history","label":"Publication History"}}]}}