{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,10,15]],"date-time":"2026-10-15T13:45:22Z","timestamp":1792071922604,"version":"4.4.0"},"reference-count":14,"publisher":"Wiley","issue":"9","license":[{"start":{"date-parts":[[2026,9,15]],"date-time":"2026-09-15T00:00:00Z","timestamp":1789430400000},"content-version":"vor","delay-in-days":14,"URL":"http:\/\/creativecommons.org\/licenses\/by\/4.0\/"},{"start":{"date-parts":[[2026,9,1]],"date-time":"2026-09-01T00:00:00Z","timestamp":1788220800000},"content-version":"tdm","delay-in-days":0,"URL":"http:\/\/doi.wiley.com\/10.1002\/tdm_license_1.1"}],"content-domain":{"domain":["aapm.onlinelibrary.wiley.com"],"crossmark-restriction":true},"short-container-title":["Medical Physics"],"published-print":{"date-parts":[[2026,9]]},"abstract":"<jats:title>Abstract<\/jats:title>\n                  <jats:sec>\n                    <jats:title>Background<\/jats:title>\n                    <jats:p>Published guidance offers four methods of static field inhomogeneity  measurement, including a bandwidth difference method. However, an error exists in the implementation of this method, which we demonstrate analytically and experimentally.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Purpose<\/jats:title>\n                    <jats:p>To propose and validate a correction to the bandwidth difference method for quantifying .<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Methods<\/jats:title>\n                    <jats:p>We outline a correction in the method for quantifying local  by measuring spatial translations rather than diameter measurements between MRI images with different receive bandwidths. To validate the approach, we acquired images of a cylindrical phantom containing a fixed array of fluid\u2010filled pins. We adjusted static field shims to create approximately linear and quadratic field perturbations and acquired high\u2010 and low\u2010bandwidth spoiled gradient echo sequences with anterior\u2010posterior (AP) and left\u2010right (LR) frequency\u2010encoding. We then measured translations of centroid pin locations between low\u2010 and high\u2010bandwidth images. Finally, we propose and validate an implementation strategy using a spherical phantom. In both cases, a vendor\u2010provided field mapping sequence provided reference homogeneity measurements.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Results<\/jats:title>\n                    <jats:p>Under manually adjusted shim settings, root\u2010mean\u2010square (RMS) and peak\u2010to\u2010peak (PP)  were 2.46 and 6.29 parts per million (PPM) respectively, measured with the field mapping technique. Results of the proposed bandwidth difference method showed strong agreement; RMS and PP  were 2.38 and 6.22 PPM respectively for AP frequency\u2010encoding and 2.38 and 6.08 PPM respectively for LR frequency\u2010encoding. In a spherical phantom, the proposed method agreed with reference measurements to within 0.25 PPM\u00a0(&lt;\u00a07%). However, PP  was underestimated using the diameter\u2010based method\u2014in a spherical phantom, measured  was 0.74 PPM compared to 3.52 and 3.76 PPM using the reference and revised methods, respectively.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Conclusions<\/jats:title>\n                    <jats:p>This work experimentally validates a revised bandwidth difference approach for  quantification, showing that it remains sensitive under spatially nonlinear ; the diameter\u2010based method is shown to be inaccurate for such cases.<\/jats:p>\n                  <\/jats:sec>","DOI":"10.1002\/mp.70673","type":"journal-article","created":{"date-parts":[[2026,9,16]],"date-time":"2026-09-16T03:16:53Z","timestamp":1789528613000},"update-policy":"https:\/\/doi.org\/10.1002\/crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["A correction to the bandwidth difference method for assessment of magnetic resonance static field homogeneity"],"prefix":"10.1002","volume":"53","author":[{"ORCID":"https:\/\/orcid.org\/0009-0007-6394-637X","authenticated-orcid":false,"given":"Joseph","family":"Wishart","sequence":"first","affiliation":[{"name":"Department of Radiology University of Washington  Seattle Washington USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Christina L.","family":"Brunnquell","sequence":"additional","affiliation":[{"name":"Department of Radiology University of Minnesota  Minneapolis Minnesota USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Daniel","family":"Vergara","sequence":"additional","affiliation":[{"name":"Department of Radiology University of Washington  Seattle Washington USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Jason","family":"Ostenson","sequence":"additional","affiliation":[{"name":"Department of Radiology University of Washington  Seattle Washington USA"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"311","published-online":{"date-parts":[[2026,9,15]]},"reference":[{"key":"e_1_2_9_2_1","doi-asserted-by":"publisher","DOI":"10.1002\/jmri.24288"},{"key":"e_1_2_9_3_1","doi-asserted-by":"publisher","DOI":"10.1016\/j.pnmrs.2008.04.001"},{"key":"e_1_2_9_4_1","doi-asserted-by":"publisher","DOI":"10.1007\/978\u20101\u201061737\u2010992\u20105_9"},{"key":"e_1_2_9_5_1","doi-asserted-by":"publisher","DOI":"10.1002\/jmri.1880070203"},{"key":"e_1_2_9_6_1","doi-asserted-by":"publisher","DOI":"10.1002\/jmri.25761"},{"key":"e_1_2_9_7_1","doi-asserted-by":"publisher","DOI":"10.2147\/RRNM.S46526"},{"key":"e_1_2_9_8_1","unstructured":"BlascheM FischerD.Magnet homogeneity and shimming.Siemens Healthcare GmbH;2017. Accessed May 29 2026.https:\/\/cdn0.scrvt.com\/39b415fb07de4d9656c7b516d8e2d907\/1800000003946047\/b36c69893983\/mreadings_mr\u2010in\u2010rt_3rd\u2010edition_magnet\u2010homogeneity\u2010and\u2010shimming_blasche_v2_1800000003946047.pdf"},{"key":"e_1_2_9_9_1","volume-title":"2015 magnetic resonance imaging quality control manual","author":"Price R","year":"2015"},{"key":"e_1_2_9_10_1","doi-asserted-by":"crossref","unstructured":"JacksonE BronskillM DrostD et\u00a0al.Acceptance testing and quality assurance procedures for magnetic resonance imaging facilities.American Association of Physicists in Medicine;2010. doi:10.37206\/101","DOI":"10.37206\/101"},{"key":"e_1_2_9_11_1","doi-asserted-by":"publisher","DOI":"10.1002\/mp.17351"},{"key":"e_1_2_9_12_1","doi-asserted-by":"publisher","DOI":"10.1118\/1.2359229"},{"key":"e_1_2_9_13_1","unstructured":"BrunnquellCL AndrewsTJ FieldenSW et\u00a0al.AAPM Task group report 325: vendor specific testing.American Association of Physicists in Medicine;2024. 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