{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,10,23]],"date-time":"2026-10-23T00:57:08Z","timestamp":1792717028553,"version":"4.5.0"},"reference-count":44,"publisher":"IOP Publishing","issue":"13","license":[{"start":{"date-parts":[[2026,7,15]],"date-time":"2026-07-15T00:00:00Z","timestamp":1784073600000},"content-version":"vor","delay-in-days":1,"URL":"https:\/\/publishingsupport.iopscience.iop.org\/iop-standard\/v1"},{"start":{"date-parts":[[2026,7,15]],"date-time":"2026-07-15T00:00:00Z","timestamp":1784073600000},"content-version":"tdm","delay-in-days":1,"URL":"https:\/\/iopscience.iop.org\/info\/page\/text-and-data-mining"}],"content-domain":{"domain":["iopscience.iop.org"],"crossmark-restriction":false},"short-container-title":["Phys. Med. Biol."],"published-print":{"date-parts":[[2026,7,14]]},"abstract":"Abstract<\/jats:title>\n \n Objective.<\/jats:italic>\n While clinical tasks require visualization of spatially complex interventional devices, typical methods to assess x-ray angiography systems performance utilize stylized test objects. The purpose of this work was to develop methods to estimate the contribution of individual x-ray angiography system pixels to test object\n \n \n \n <\/jats:tex-math>\n \n \n S<\/mml:mi>\n N<\/mml:mi>\n \n \n R<\/mml:mi>\n 2<\/mml:mn>\n <\/mml:msup>\n <\/mml:mrow>\n <\/mml:mrow>\n <\/mml:math>\n <\/jats:inline-formula>\n , thus providing for the use of clinical devices as test objects.\n Approach.<\/jats:italic>\n Theory to estimate the contribution of individual pixels (\n \n \n \n <\/jats:tex-math>\n \n \n s<\/mml:mi>\n n<\/mml:mi>\n \n \n r<\/mml:mi>\n 2<\/mml:mn>\n <\/mml:msup>\n <\/mml:mrow>\n <\/mml:mrow>\n <\/mml:math>\n <\/jats:inline-formula>\n ) to test object\n \n \n \n <\/jats:tex-math>\n \n \n S<\/mml:mi>\n N<\/mml:mi>\n \n \n R<\/mml:mi>\n 2<\/mml:mn>\n <\/mml:msup>\n <\/mml:mrow>\n <\/mml:mrow>\n <\/mml:math>\n <\/jats:inline-formula>\n was derived. For each pixel, the \u2018signal\u2019 was the mean pixel value difference between a set of test signal present and absent images. \u2018Noise\u2019 was estimated as the pixel-specific total covariance (\n \n \n \n <\/jats:tex-math>\n \n \n \n \n \u03c9<\/mml:mi>\n 2<\/mml:mn>\n <\/mml:msup>\n <\/mml:mrow>\n <\/mml:mrow>\n <\/mml:math>\n <\/jats:inline-formula>\n ) calculated within a local pixel neighborhood. Test object\n \n \n \n <\/jats:tex-math>\n \n \n S<\/mml:mi>\n N<\/mml:mi>\n R<\/mml:mi>\n <\/mml:mrow>\n <\/mml:math>\n <\/jats:inline-formula>\n from this pixel-specific observer (PSO) was compared to that from a Hotelling observer which used pixel values as variables (PHO) and a Gabor channelized Hotelling observer (CHO). Bias from finite sampling and detector electronic noise was managed by established methods. Image samples were acquired using stationary iodine disks (diameter 0.5\u20134.0 mm) and pediatric interventional devices as test objects. Quantum fluence was varied over a range of 8\n x<\/jats:italic>\n to mimic exposure conditions for both fluoroscopy and angiography.\n Main results.<\/jats:italic>\n For the iodine disk test objects,\n \n \n \n <\/jats:tex-math>\n \n \n S<\/mml:mi>\n N<\/mml:mi>\n R<\/mml:mi>\n <\/mml:mrow>\n <\/mml:math>\n <\/jats:inline-formula>\n was in the range \u223c1.0\u201332.\n \n \n \n <\/jats:tex-math>\n \n \n S<\/mml:mi>\n N<\/mml:mi>\n R<\/mml:mi>\n <\/mml:mrow>\n <\/mml:math>\n <\/jats:inline-formula>\n estimates by the PSO method were linear with object size, x-ray fluence, and PHO and CHO estimates. Pixel-specific\n \n \n \n <\/jats:tex-math>\n \n \n 2<\/mml:mn>\n \n D<\/mml:mi>\n <\/mml:mrow>\n \n \u2009<\/mml:mtext>\n <\/mml:mrow>\n \n s<\/mml:mi>\n n<\/mml:mi>\n <\/mml:mrow>\n \n \n \n r<\/mml:mi>\n <\/mml:mrow>\n 2<\/mml:mn>\n <\/mml:msup>\n <\/mml:mrow>\n <\/mml:mrow>\n <\/mml:math>\n <\/jats:inline-formula>\n maps of implantable devices demonstrated that the pixel-specific approach preserved the high spatial fidelity of the x-ray angiography system, including the effects of focal spot blur.\n Significance.<\/jats:italic>\n That test object\n \n \n \n <\/jats:tex-math>\n \n \n S<\/mml:mi>\n N<\/mml:mi>\n R<\/mml:mi>\n <\/mml:mrow>\n <\/mml:math>\n <\/jats:inline-formula>\n estimated by the pixel-specific methods were consistent with those from the PHO and CHO provides mutual support for the accuracy of each method. The newly proposed approach provides for the use of spatially complex clinical devices as test objects.\n <\/jats:p>","DOI":"10.1088\/1361-6560\/ae79cf","type":"journal-article","created":{"date-parts":[[2026,6,8]],"date-time":"2026-06-08T22:54:13Z","timestamp":1780959253000},"page":"135042","update-policy":"https:\/\/doi.org\/10.1088\/crossmark-policy","source":"Crossref","is-referenced-by-count":1,"title":["A pixel-specific model observer for high-fidelity assessment of x-ray angiography imaging system performance"],"prefix":"10.1088","volume":"71","author":[{"ORCID":"https:\/\/orcid.org\/0000-0001-8609-4308","authenticated-orcid":true,"given":"Kenneth A","family":"Fetterly","sequence":"first","affiliation":[{"name":"Cardiovascular Medicine"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"266","published-online":{"date-parts":[[2026,7,15]]},"reference":[{"key":"pmbae79cfbib1","doi-asserted-by":"publisher","first-page":"473","DOI":"10.1364\/JOSAA.18.000473","type":"journal-article","article-title":"Human- and model-observer performance in ramp-spectrum noise: effects of regularization and object variability","volume":"18","author":"Abbey","year":"2001","journal-title":"J. Opt. Soc. Am. A"},{"key":"pmbae79cfbib2","doi-asserted-by":"publisher","first-page":"714","DOI":"10.1002\/mp.13342","type":"journal-article","article-title":"Can a channelized Hotelling observer assess image quality in acquired mammographic images of an anthropomorphic breast phantom including image processing?","volume":"46","author":"Balta","year":"2019","journal-title":"Med. Phys."},{"key":"pmbae79cfbib3","doi-asserted-by":"publisher","first-page":"299","DOI":"10.1117\/12.430869","type":"journal-article","article-title":"Megalopinakophobia: its symptoms and cures","volume":"4320","author":"Barrett","year":"2001"},{"key":"pmbae79cfbib4","doi-asserted-by":"publisher","first-page":"9758","DOI":"10.1073\/pnas.90.21.9758","type":"journal-article","article-title":"Model observers for assessment of image quality","volume":"90","author":"Barrett","year":"1993","journal-title":"Proc. Natl Acad. Sci. USA"},{"key":"pmbae79cfbib5","doi-asserted-by":"publisher","author":"Barrett","year":"2004","DOI":"10.1126\/science.1094186","type":"book"},{"key":"pmbae79cfbib6","first-page":"401","type":"journal-article","article-title":"On a measure of divergence between two multinomial populations","volume":"7","author":"Bhattacharyya","year":"1946","journal-title":"Indian J. Stat."},{"key":"pmbae79cfbib7","doi-asserted-by":"publisher","first-page":"7159","DOI":"10.1088\/0031-9155\/58\/20\/7159","type":"journal-article","article-title":"Evaluation of the channelized Hotelling observer with an internal-noise model in a train-test paradigm for cardiac SPECT defect detection","volume":"58","author":"Brankov","year":"2013","journal-title":"Phys. Med. Biol."},{"key":"pmbae79cfbib8","doi-asserted-by":"publisher","first-page":"633","DOI":"10.1364\/JOSAA.16.000633","type":"journal-article","article-title":"The Rose model, revisited","volume":"16","author":"Burgess","year":"1999","journal-title":"J. Opt. Soc. Am. A"},{"key":"pmbae79cfbib9","doi-asserted-by":"publisher","DOI":"10.1088\/1361-6560\/ad9541","type":"journal-article","article-title":"Statistical biases correction in channelized Hotelling model observers","volume":"69","author":"Desponds","year":"2024","journal-title":"Phys. Med. Biol."},{"key":"pmbae79cfbib10","doi-asserted-by":"publisher","first-page":"1428","DOI":"10.1109\/TMI.2015.2395433","type":"journal-article","article-title":"Derivation of an observer model adapted to irregular signals based on convolution channels","volume":"34","author":"Diaz","year":"2015","journal-title":"IEEE Trans. Med. Imaging"},{"key":"pmbae79cfbib11","author":"Dodge","year":"2008","type":"book"},{"key":"pmbae79cfbib12","doi-asserted-by":"publisher","first-page":"460","DOI":"10.1364\/OE.11.000460","type":"journal-article","article-title":"Automated computer evaluation and optimization of image compression of x-ray coronary angiograms for signal known exactly detection tasks","volume":"11","author":"Eckstein","year":"2002","journal-title":"Opt. Express"},{"key":"pmbae79cfbib13","doi-asserted-by":"publisher","first-page":"1714","DOI":"10.1002\/mp.16961","type":"journal-article","article-title":"Channelized Hotelling observer-based low-contrast detectability on the ACR CT accreditation phantom: part II","volume":"51","author":"Fan","year":"2024","journal-title":"Repeatability Study. Med Phys."},{"key":"pmbae79cfbib14","doi-asserted-by":"publisher","first-page":"0155031","DOI":"10.1117\/1.JMI.2.1.015503","type":"journal-article","article-title":"Implementation of a channelized Hotelling observer model to assess image quality of x-ray angiography systems","volume":"2","author":"Favazza","year":"2015","journal-title":"J. Med. Imaging"},{"key":"pmbae79cfbib15","doi-asserted-by":"publisher","first-page":"4888","DOI":"10.1002\/mp.13192","type":"journal-article","article-title":"Performance assessment of active vs passive pixel x-ray angiography detector systems using a bias-corrected channelized Hotelling observer and adult patient-equivalent experimental conditions","volume":"45","author":"Fetterly","year":"2018","journal-title":"Med. Phys."},{"key":"pmbae79cfbib16","type":"dataset","article-title":"X-ray angiography model observer dataset","author":"Fetterly","year":"2026","unstructured":"Fetterly K A 2026 X-ray angiography model observer dataset Mayo Clinic Research (available at: www.mayo.edu\/research\/FetterlyPMB2026 )"},{"key":"pmbae79cfbib17","doi-asserted-by":"publisher","first-page":"5606","DOI":"10.1088\/0031-9155\/61\/15\/5606","type":"journal-article","article-title":"Direct estimation and correction of bias from temporally variable non-stationary noise in a channelized Hotelling model observer","volume":"61","author":"Fetterly","year":"2016","journal-title":"Phys. Med. Biol."},{"key":"pmbae79cfbib18","first-page":"SU\u2013330\u2013GPD\u2013D","type":"journal-article","article-title":"Estimation of pixel-specific contributions to Hotelling\u2019s T2 to create detailed Student\u2019s t2 maps of complex test objects: application to pediatric implantable device","volume":"50","author":"Fetterly","year":"2025a","journal-title":"Med. Phys."},{"key":"pmbae79cfbib19","article-title":"High fidelity, multivariate assessment of x-ray angiography system performance","author":"Fetterly","year":"2025b","type":"book"},{"key":"pmbae79cfbib20","doi-asserted-by":"publisher","first-page":"945","DOI":"10.1364\/JOSAA.4.000945","type":"journal-article","article-title":"Hotelling trace criterion and its correlation with human-observer performance","volume":"4","author":"Fiete","year":"1987","journal-title":"J. Opt. Soc. Am. A"},{"key":"pmbae79cfbib21","first-page":"90","type":"journal-article","article-title":"Application of \u201cStudent\u2019s\u201d distribution","volume":"5","author":"Fisher","year":"1925","journal-title":"Metron"},{"key":"pmbae79cfbib22","doi-asserted-by":"publisher","first-page":"873","DOI":"10.1109\/34.31448","type":"journal-article","article-title":"Effects of sample size in classifier design","volume":"11","author":"Fukunaga","year":"1989","journal-title":"IEEE Trans. Pattern Anal. Mach. Intell."},{"key":"pmbae79cfbib23","doi-asserted-by":"publisher","first-page":"83","DOI":"10.1118\/1.2140117","type":"journal-article","article-title":"Toward objective and quantitative evaluation of imaging systems using images of phantoms","volume":"33","author":"Gagne","year":"2006","journal-title":"Med. Phys."},{"key":"pmbae79cfbib24","doi-asserted-by":"publisher","first-page":"1725","DOI":"10.1364\/JOSAA.20.001725","type":"journal-article","article-title":"Validating the use of channels to estimate the ideal linear observer","volume":"20","author":"Gallas","year":"2003","journal-title":"J. Opt. Soc. Am. A"},{"key":"pmbae79cfbib25","doi-asserted-by":"publisher","first-page":"3638","DOI":"10.1002\/mp.14813","type":"journal-article","article-title":"Task-specific efficient channel selection and bias management for Gabor function channelized Hotelling observer model for the assessment of x-ray angiography system performance","volume":"48","author":"Gomez-Cardona","year":"2021","journal-title":"Med. Phys."},{"key":"pmbae79cfbib26","doi-asserted-by":"publisher","first-page":"6737","DOI":"10.1002\/mp.16686","type":"journal-article","article-title":"Adaptation of a channelized Hotelling observer model to accommodate anthropomorphic backgrounds and moving test objects in x-ray angiography","volume":"50","author":"Gomez-Cardona","year":"2023","journal-title":"Med. Phys."},{"key":"pmbae79cfbib27","doi-asserted-by":"publisher","first-page":"360","DOI":"10.1214\/aoms\/1177732979","type":"journal-article","article-title":"The generalization of Student\u2019s ratio","volume":"2","author":"Hotelling","year":"1931","journal-title":"Ann. Math. Statist."},{"key":"pmbae79cfbib28","doi-asserted-by":"publisher","DOI":"10.1016\/j.ejmp.2023.102556","type":"journal-article","article-title":"Spatio-temporal generalized model observers methods for low contrast detectability assessment in digital angiography: application to moving targets","volume":"108","author":"Ingraito","year":"2023","journal-title":"Phys. Med."},{"key":"pmbae79cfbib29","author":"Johnson","year":"2002","type":"book"},{"key":"pmbae79cfbib30","first-page":"541","type":"journal-article","article-title":"On tests and measures of group divergence","volume":"26","author":"Mahalanobis","year":"1930","journal-title":"J. Proc. Asiat. Soc. Bengal."},{"key":"pmbae79cfbib31","first-page":"49","type":"journal-article","article-title":"On the generalized distance in statistics","volume":"2","author":"Mahalanobis","year":"1936","journal-title":"Proc. Natl. Inst. Sci. India."},{"key":"pmbae79cfbib32","doi-asserted-by":"publisher","first-page":"2447","DOI":"10.1364\/JOSAA.4.002447","type":"journal-article","article-title":"Addition of a channel mechanism to the ideal-observer model","volume":"4","author":"Myers","year":"1987","journal-title":"J. Opt. Soc. Am. A"},{"key":"pmbae79cfbib33","doi-asserted-by":"publisher","first-page":"1717","DOI":"10.1016\/j.ejmp.2016.11.002","type":"journal-article","article-title":"CT image quality assessment by a channelized Hotelling observer (CHO): application to protocol optimization","volume":"32","author":"Noferini","year":"2016","journal-title":"Phys. Med."},{"key":"pmbae79cfbib34","doi-asserted-by":"publisher","first-page":"8","DOI":"10.1016\/j.ejmp.2018.12.033","type":"journal-article","article-title":"Systematic approach to a channelized Hotelling model observer implementation for a physical phantom containing mass-like lesions: application to digital breast tomosynthesis","volume":"58","author":"Petrov","year":"2019","journal-title":"Phys. Med."},{"key":"pmbae79cfbib35","doi-asserted-by":"publisher","first-page":"196","DOI":"10.1364\/JOSA.38.000196","type":"journal-article","article-title":"The sensitivity performance of the human eye on an absolute scale","volume":"38","author":"Rose","year":"1948","journal-title":"J. Opt. Soc. Am."},{"key":"pmbae79cfbib36","author":"Samei","year":"2018","type":"book"},{"key":"pmbae79cfbib37","doi-asserted-by":"publisher","first-page":"1","DOI":"10.2307\/2331554","type":"journal-article","article-title":"The probable error of a mean","volume":"6","author":"Student","year":"1908","journal-title":"Biometrika"},{"key":"pmbae79cfbib38","doi-asserted-by":"publisher","DOI":"10.1088\/1361-6560\/ab39c4","type":"journal-article","article-title":"Integration of high velocity test object motion into a channelized Hotelling observer for the assessment of x-ray angiography systems","volume":"64","author":"Tao","year":"2019","journal-title":"Phys. Med. Biol."},{"key":"pmbae79cfbib39","doi-asserted-by":"publisher","first-page":"1761","DOI":"10.1088\/0031-9155\/38\/12\/006","type":"journal-article","article-title":"SNR and noise measurements for medical imaging: II. Application to fluoroscopic x-ray equipment","volume":"38","author":"Tapiovaara","year":"1993","journal-title":"Phys. Med. Biol."},{"key":"pmbae79cfbib40","doi-asserted-by":"publisher","first-page":"176","DOI":"10.1093\/biomet\/13.2-3.176","type":"journal-article","article-title":"A first study of the Burmese skull","volume":"13","author":"Tildesley","year":"1921","journal-title":"Biometrika"},{"key":"pmbae79cfbib41","doi-asserted-by":"publisher","first-page":"89","DOI":"10.1016\/j.ejmp.2019.06.015","type":"journal-article","article-title":"Model observers for low contrast detectability evaluation in dynamic angiography: a feasible approach","volume":"64","author":"Villa","year":"2019","journal-title":"Phys. Med."},{"key":"pmbae79cfbib42","doi-asserted-by":"publisher","first-page":"1406","DOI":"10.1126\/science.351.6280.1406","type":"journal-article","article-title":"Pseudonymous fame","volume":"351","author":"Wendl","year":"2016","journal-title":"Science"},{"key":"pmbae79cfbib43","doi-asserted-by":"publisher","first-page":"453","DOI":"10.1109\/TMI.2014.2360496","type":"journal-article","article-title":"Exact confidence intervals for channelized Hotelling observer performance in image quality studies","volume":"34","author":"Wunderlich","year":"2015","journal-title":"IEEE Trans. Med. Imaging"},{"key":"pmbae79cfbib44","doi-asserted-by":"publisher","first-page":"3389","DOI":"10.1088\/0031-9155\/59\/13\/3389","type":"journal-article","article-title":"Correlation between human and model observer performance for discrimination task in CT","volume":"59","author":"Zhang","year":"2014","journal-title":"Phys. Med. Biol."}],"container-title":["Physics in Medicine & Biology"],"original-title":[],"link":[{"URL":"https:\/\/iopscience.iop.org\/article\/10.1088\/1361-6560\/ae79cf","content-type":"text\/html","content-version":"am","intended-application":"text-mining"},{"URL":"https:\/\/iopscience.iop.org\/article\/10.1088\/1361-6560\/ae79cf\/pdf","content-type":"application\/pdf","content-version":"am","intended-application":"text-mining"},{"URL":"https:\/\/iopscience.iop.org\/article\/10.1088\/1361-6560\/ae79cf","content-type":"text\/html","content-version":"vor","intended-application":"text-mining"},{"URL":"https:\/\/iopscience.iop.org\/article\/10.1088\/1361-6560\/ae79cf\/pdf","content-type":"application\/pdf","content-version":"vor","intended-application":"text-mining"},{"URL":"https:\/\/iopscience.iop.org\/article\/10.1088\/1361-6560\/ae79cf\/pdf","content-type":"application\/pdf","content-version":"am","intended-application":"syndication"},{"URL":"https:\/\/iopscience.iop.org\/article\/10.1088\/1361-6560\/ae79cf\/pdf","content-type":"application\/pdf","content-version":"vor","intended-application":"syndication"},{"URL":"https:\/\/iopscience.iop.org\/article\/10.1088\/1361-6560\/ae79cf\/pdf","content-type":"application\/pdf","content-version":"am","intended-application":"similarity-checking"},{"URL":"https:\/\/iopscience.iop.org\/article\/10.1088\/1361-6560\/ae79cf\/pdf","content-type":"application\/pdf","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2026,7,15]],"date-time":"2026-07-15T10:17:07Z","timestamp":1784110627000},"score":1,"resource":{"primary":{"URL":"https:\/\/iopscience.iop.org\/article\/10.1088\/1361-6560\/ae79cf"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2026,7,14]]},"references-count":44,"journal-issue":{"issue":"13","published-online":{"date-parts":[[2026,7,15]]},"published-print":{"date-parts":[[2026,7,14]]}},"URL":"https:\/\/doi.org\/10.1088\/1361-6560\/ae79cf","relation":{},"ISSN":["0031-9155","1361-6560"],"issn-type":[{"value":"0031-9155","type":"print"},{"value":"1361-6560","type":"electronic"}],"subject":[],"published":{"date-parts":[[2026,7,14]]},"assertion":[{"value":"A pixel-specific model observer for high-fidelity assessment of x-ray angiography imaging system performance","name":"article_title","label":"Article Title"},{"value":"Physics in Medicine & Biology","name":"journal_title","label":"Journal Title"},{"value":"paper","name":"article_type","label":"Article Type"},{"value":"\u00a9 2026 Institute of Physics and Engineering in Medicine. All rights, including for text and data mining, AI training, and similar technologies, are reserved.","name":"copyright_information","label":"Copyright Information"},{"value":"2026-03-16","name":"date_received","label":"Date Received","group":{"name":"publication_dates","label":"Publication dates"}},{"value":"2026-06-08","name":"date_accepted","label":"Date Accepted","group":{"name":"publication_dates","label":"Publication dates"}},{"value":"2026-07-15","name":"date_epub","label":"Online publication date","group":{"name":"publication_dates","label":"Publication dates"}}]}}