{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,6,19]],"date-time":"2026-06-19T10:52:54Z","timestamp":1781866374100,"version":"3.54.5"},"reference-count":31,"publisher":"Springer Science and Business Media LLC","issue":"7","license":[{"start":{"date-parts":[[2026,2,19]],"date-time":"2026-02-19T00:00:00Z","timestamp":1771459200000},"content-version":"tdm","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0"},{"start":{"date-parts":[[2026,2,19]],"date-time":"2026-02-19T00:00:00Z","timestamp":1771459200000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0"}],"funder":[{"name":"Institutional Research Grant from Siemens Healthineers"}],"content-domain":{"domain":["link.springer.com"],"crossmark-restriction":false},"short-container-title":["Eur Radiol"],"abstract":"<jats:title>Abstract<\/jats:title>\n                  <jats:sec>\n                    <jats:title>Objectives<\/jats:title>\n                    <jats:p>Part I of this study introduced a new photon-counting detector (PCD-)CT protocol for coronary artery calcium (CAC) scoring using 120 kVp, 75% dose, thin slices, quantum iterative reconstructions (IR) 2, leading to a significant reduction of score variability. The second part evaluated the potential of virtual monoenergetic image (VMI) reconstruction in further reducing score variability with PCD-CT.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Materials and methods<\/jats:title>\n                    <jats:p>CAC scoring was performed on PCD-CT with a chest phantom containing nine calcifications using the optimized PCD-CT protocol from Part I. Images were reconstructed at different VMI levels (50\u201380\u2009keV, 5 keV-steps), with adjusted CAC thresholds to maintain density equivalence to 70\u2009keV. CAC scores, image noise, and calcification detectability were investigated. Results were compared to standard PCD-CT, EID-CT and previously proposed EID-CT protocols.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Results<\/jats:title>\n                    <jats:p>Using 65\u2009keV reconstructions, score variability decreased by 9% compared to the optimized PCD-CT protocol from Part I, by 43% vs. the standard PCD-CT, by 78% vs. the standard EID-CT, and by 69% vs. the proposed EID-CT protocol. Image noise remained within targets, eliminating the risk of false-positives. Calcification detectability was comparable to the optimized PCD-CT protocol (7.1\u2009\u00b1\u20090.6 vs. 7.1\u2009\u00b1\u20090.8). Calcium volume and mass scores from the keV-optimized PCD protocol were closer to the physical reference compared to scores from the standard PCD protocol.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Conclusions<\/jats:title>\n                    <jats:p>Score variability and calcification detectability in PCD-CT-based CAC scoring can be further improved when augmenting an optimized PCD-CT protocol at 65\u2009keV. In addition to reducing the radiation dose, this protocol may enable more consistent CAC quantification and seems to perform even better than the proposed, multivendor EID-CT protocol.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Key Points<\/jats:title>\n                    <jats:p>\n                      <jats:bold>\n                        <jats:italic>Question<\/jats:italic>\n                      <\/jats:bold>\n                      <jats:italic>Coronary calcium scoring lacks reproducibility. Adding virtual monoenergetic imaging with adapted thresholds to a pre-optimized photon-counting CT protocol may further improve score variability.<\/jats:italic>\n                    <\/jats:p>\n                    <jats:p>\n                      <jats:bold>\n                        <jats:italic>Findings<\/jats:italic>\n                      <\/jats:bold>\n                      <jats:italic>A 120 kVp, 75%-dose, thin-slice photon-counting CT protocol at 65\u2009keV achieved the lowest coronary calcium score variability compared to previous protocols.<\/jats:italic>\n                    <\/jats:p>\n                    <jats:p>\n                      <jats:bold>\n                        <jats:italic>Clinical relevance<\/jats:italic>\n                      <\/jats:bold>\n                      <jats:italic>Minimizing variability in coronary calcium scoring improves the technical reliability of serial measurements. The additional use of virtual monoenergetic imaging further reduces variability in photon-counting CT, supporting a precise and consistent cardiovascular risk assessment.<\/jats:italic>\n                    <\/jats:p>\n                  <\/jats:sec>","DOI":"10.1007\/s00330-026-12356-3","type":"journal-article","created":{"date-parts":[[2026,2,19]],"date-time":"2026-02-19T17:37:50Z","timestamp":1771522670000},"page":"5557-5566","update-policy":"https:\/\/doi.org\/10.1007\/springer_crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["Coronary artery calcium scoring: expanding the new standard by photon-counting detector CT Part II: Impact of virtual monoenergetic image reconstructions with adjusted calcium scoring thresholds"],"prefix":"10.1007","volume":"36","author":[{"given":"Nicola","family":"Fink","sequence":"first","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Lennart R.","family":"Koetzier","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Emese","family":"Zsarnoczay","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Milan","family":"Vecsey-Nagy","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Dmitrij","family":"Kravchenko","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Muhammad Taha","family":"Hagar","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Jim","family":"O\u2019Doherty","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Moritz C.","family":"Halfmann","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Pal","family":"Suranyi","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Gijs D.","family":"van Praagh","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Jens","family":"Ricke","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Pal","family":"Maurovich-Horvat","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Tobias","family":"B\u00e4uerle","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Martin J.","family":"Willemink","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-2781-7462","authenticated-orcid":false,"given":"Akos","family":"Varga-Szemes","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Tilman","family":"Emrich","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"297","published-online":{"date-parts":[[2026,2,19]]},"reference":[{"key":"12356_CR1","doi-asserted-by":"publisher","first-page":"4459","DOI":"10.1007\/s00330-023-10439-z","volume":"34","author":"M Osborne-Grinter","year":"2024","unstructured":"Osborne-Grinter M, Ali A, Williams MC (2024) Prevalence and clinical implications of coronary artery calcium scoring on non-gated thoracic computed tomography: a systematic review and meta-analysis. 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Tilman Emrich received a speaker fee and travel support from Siemens Medical Solutions USA Inc., and institutional research support from Siemens Healthineers. Jim O\u2019Doherty is an employee of Siemens Medical Solutions USA Inc. M.J.W. is a Junior Deputy Editor of\n                      European Radiology\n                      and, as such, did not participate in the selection or review processes for this article. The remaining authors declare no conflicts of interest.","order":3,"name":"Ethics","group":{"name":"EthicsHeading","label":"Conflict of interest"}},{"value":"No complex statistical methods were necessary for this paper.","order":4,"name":"Ethics","group":{"name":"EthicsHeading","label":"Statistics and biometry"}},{"value":"This phantom study did not involve humans or animals. Therefore, Institutional Review Board approval and informed consent were not required.","order":5,"name":"Ethics","group":{"name":"EthicsHeading","label":"Informed consent"}},{"value":"Institutional Review Board approval was not required because this is a phantom study.","order":6,"name":"Ethics","group":{"name":"EthicsHeading","label":"Ethical approval"}},{"value":"The current study is based on a phantom experiment and does not involve human or animal subjects; therefore, IRB approval and informed consent were not required. There is no overlap with previously published work. However, we would like to note that this study is methodologically based on the phantom study published by van Praagh et al [\n                      \n                      ], which established a new protocol for CAC scoring on EID-CT systems. Our work adapts their validated approach exclusively to a PCD-CT system and directly compares CAC score reproducibility between the proposed PCD-CT protocol and previous protocols, including the proposed EID-CT protocol. We would like to confirm that this paper (both Part I and Part II) is original and is not under consideration elsewhere. It has not been published in any form previously.","order":7,"name":"Ethics","group":{"name":"EthicsHeading","label":"Study subjects or cohorts overlap"}},{"order":8,"name":"Ethics","group":{"name":"EthicsHeading","label":"Methodology"}}]}}