{
  "abstract": "Background Photon-counting cardiac CT (PCCT) overcomes conventional CT limitations by combining improved spectral characterisation with enhanced geometric fidelity. Myocardial injury characterisation by late iodine enhancement (LIE) PCCT (Flash, dual-scan analysis) compares favourably to cardiovascular magnetic resonance (CMR) characterisation in ST-segment elevation acute coronary syndrome (STEACS). This study provides an intra-individual comparison of PCCT acquisition and analysis workflows for quantifying microvascular obstruction (MVO) and infarct size (IS).Methods Between 11/2024 and 04/2025, 19 consecutive patients (OxAMI) underwent PCCT LIE myocardial evaluation with a first-generation NAEOTOM Alpha system (Siemens Healthineers). All participants underwent PCCTA(0.6 gI/kg), followed by an 8-minute delay and two consecutive LIE acquisitions: a high-pitch spiral technique (Flash) and a sequential technique (Flex) with a 250-350ms window. Same-day late gadolinium enhancement (LGE) CMR (1.5T, Siemens Healthineers) was performed in 12 patients. PCCT LIE myocardial analysis was based on iodine-derived extracellular volume, using dual-scan, Flash-based and single-scan, Flex-based workflows (figures 1 and 2).Results There is excellent agreement between a single-scan, Flex-based and a dual-scan, Flash-based PCCT workflow for MVO and IS; intraclass correlation coefficient (ICC) 0.98 95%CI:0.95-0.99 and 0.96 95%CI:0.89-0.98, respectively. Bland-Altman analysis shows no systematic bias and acceptable limits of agreement for MVO and IS evaluation; mean bias/limits of agreement: 0.03%/3.14% and 0.18%/6.01%, respectively. There is good agreement between a single-scan, Flex-based PCCT and CMR LGE for MVO and IS evaluation; ICC 0.79 95%CI:0.28-0.94 and 0.90 95%CI:0.63-0.96), respectively.Conclusion Single-scan Flex LIE PCCT provides accurate quantification of MVO and IS, with good level of agreement to CMR LGE and dual-scan Flash LIE PCCT. Question:In patients with ST-segment elevation acute coronary syndrome (STEACS), how does the single-scan Flex-based photon-counting CT (PCCT) workflow compare to the dual-scan Flash-based workflow and cardiovascular magnetic resonance (CMR) in quantifying microvascular obstruction (MVO) and infarct size (IS)?A. It shows poor agreement with both dual-scan Flash PCCT and CMR, limiting its clinical utility.B. It demonstrates excellent agreement with dual-scan Flash PCCT but no agreement with CMR.C. It demonstrates excellent agreement with dual-scan Flash PCCT and good agreement with CMR.D. It overestimates MVO and IS compared to both dual-scan Flash PCCT and CMR.Correct answer:Abstract 13 Figure 2Abstract 13 Figure 1C. It demonstrates excellent agreement with dual-scan Flash PCCT and good agreement with CMR.",
  "authors": [
    {
      "affiliations": [
        "Acute Multidisciplinary Imaging & Interventional Centre (AMIIC), Division of Cardiovascular Medicine, Radcliffe Department of Medicine, University of Oxford, United Kingdom"
      ],
      "name": "Athanasia Panopouloua"
    },
    {
      "affiliations": [
        "Acute Multidisciplinary Imaging & Interventional Centre (AMIIC), Division of Cardiovascular Medicine, Radcliffe Department of Medicine, University of Oxford, United Kingdom"
      ],
      "name": "Robyn Farralla"
    },
    {
      "affiliations": [
        "Oxford University Hospitals NHS Trust, John Radcliffe Hospital, Oxford, United Kingdom"
      ],
      "name": "Rafail A Kotroniasa"
    },
    {
      "affiliations": [
        "Acute Multidisciplinary Imaging & Interventional Centre (AMIIC), Division of Cardiovascular Medicine, Radcliffe Department of Medicine, University of Oxford, United Kingdom"
      ],
      "name": "James Harrisona"
    },
    {
      "affiliations": [
        "Oxford University Hospitals NHS Trust, John Radcliffe Hospital, Oxford, United Kingdom"
      ],
      "name": "Leonardo Portolana"
    },
    {
      "affiliations": [
        "Oxford Centre for Clinical Magnetic Resonance Research (OCMR), Division of Cardiovascular"
      ],
      "name": "Cheng Xiea"
    },
    {
      "affiliations": [
        "Acute Multidisciplinary Imaging & Interventional Centre (AMIIC), Division of Cardiovascular Medicine, Radcliffe Department of Medicine, University of Oxford, United Kingdom"
      ],
      "name": "Sheena Thomasa"
    },
    {
      "affiliations": [
        "Acute Multidisciplinary Imaging & Interventional Centre (AMIIC), Division of Cardiovascular Medicine, Radcliffe Department of Medicine, University of Oxford, United Kingdom"
      ],
      "name": "Vanessa M Ferreirac"
    },
    {
      "affiliations": [
        "Acute Multidisciplinary Imaging & Interventional Centre (AMIIC), Division of Cardiovascular Medicine, Radcliffe Department of Medicine, University of Oxford, United Kingdom"
      ],
      "name": "Betty Ramanc"
    },
    {
      "affiliations": [
        "Oxford University Hospitals NHS Trust, John Radcliffe Hospital, Oxford, United Kingdom"
      ],
      "name": "Jeremy P Langrish"
    },
    {
      "affiliations": [
        "Oxford University Hospitals NHS Trust, John Radcliffe Hospital, Oxford, United Kingdom"
      ],
      "name": "Andrew J Lucking"
    },
    {
      "affiliations": [
        "Acute Multidisciplinary Imaging & Interventional Centre (AMIIC), Division of Cardiovascular Medicine, Radcliffe Department of Medicine, University of Oxford, United Kingdom"
      ],
      "name": "Jonathan Dentona"
    },
    {
      "affiliations": [
        "Oxford University Hospitals NHS Trust, John Radcliffe Hospital, Oxford, United Kingdom"
      ],
      "name": "Nikant Sabharwal"
    },
    {
      "affiliations": [
        "Oxford University Hospitals NHS Trust, John Radcliffe Hospital, Oxford, United Kingdom"
      ],
      "name": "Giovanni L De Mariaa"
    },
    {
      "affiliations": [
        "Acute Multidisciplinary Imaging & Interventional Centre (AMIIC), Division of Cardiovascular Medicine, Radcliffe Department of Medicine, University of Oxford, United Kingdom"
      ],
      "name": "Keith M Channona"
    },
    {
      "affiliations": [
        "Acute Multidisciplinary Imaging & Interventional Centre (AMIIC), Division of Cardiovascular Medicine, Radcliffe Department of Medicine, University of Oxford, United Kingdom"
      ],
      "name": "Stefan Neubauer"
    },
    {
      "affiliations": [
        "Acute Multidisciplinary Imaging & Interventional Centre (AMIIC), Division of Cardiovascular Medicine, Radcliffe Department of Medicine, University of Oxford, United Kingdom"
      ],
      "name": "Charalambos Antoniadesa"
    },
    {
      "affiliations": [
        "Acute Multidisciplinary Imaging & Interventional Centre (AMIIC), Division of Cardiovascular Medicine, Radcliffe Department of Medicine, University of Oxford, United Kingdom",
        "Oxford University Hospitals NHS Trust, John Radcliffe Hospital, Oxford, United Kingdom",
        "Oxford Centre for Clinical Magnetic Resonance Research (OCMR), Division of Cardiovascular"
      ],
      "name": "on behalf of the Oxford Acute Myocardial Infarction (OxAMI) Study investigators"
    }
  ],
  "title": "13 Single-scan, sequential photon-counting CT for myocardial injury assessment in STEACS: comparison with dual-scan PCCT and CMR",
  "uid": "cb785227-628e-5929-8e3a-14a608b54e51"
}