{
  "abstract": "BackgroundThe phosphocreatine-to-ATP ratio (PCr/ATP), measurable by 3{superscript 1}P magnetic resonance spectroscopic imaging (3{superscript 1}P-MRSI), is a sensitive marker of myocardial energetic reserve. Regional energetic-mechanical coupling, evaluable only per-segment to avoid confounding from spatially heterogeneous disease, represents an important target for cardiac metabolic trials. We extend our previously validated 7T regional 3{superscript 1}P-MRSI approach to patients with cardiovascular disease.\n\nMethodsTwenty-one participants underwent same-day 7T 3{superscript 1}P-MRSI and 3T CMR: 9 healthy volunteers, 4 with type 2 diabetes, 5 with heart failure, and 3 with ischaemic cardiomyopathy. PCr/ATP was mapped across six mid-ventricular AHA segments. Ejection fraction, global longitudinal strain, peak filling rate, and regional circumferential and radial strain were derived from 3T CMR. Group differences were assessed by Kruskal-Wallis test with Bonferroni-corrected pairwise comparisons; segment-level associations by per-segment Spearman correlation and linear mixed effects models.\n\nResultsPCr/ATP differed significantly across groups (p = 0.005, {superscript 2} = 0.58), ranging from 1.78 {+/-} 0.21 in healthy volunteers to 1.10 {+/-} 0.28 in heart failure. Mean PCr/ATP correlated with ejection fraction (rs = 0.65, p = 0.002), global longitudinal strain (rs = -0.63, p < 0.001), and peak filling rate (rs = 0.52, p = 0.023). Segment-level energetic-mechanical coupling was significant in the anteroseptal and inferoseptal segments (circumferential strain rs = -0.49 to -0.56; radial strain rs = 0.43 to 0.57, all p < 0.05), with no significant associations in other segments, consistent with a displacement-related measurement quality gradient. In ischaemic patients, PCr/ATP was significantly lower in infarct segments (0.79 {+/-} 0.20) than remote myocardium (1.33 {+/-} 0.22, p = 0.008, r = 0.62). All three ischaemic patients demonstrated remote PCr/ATP below the healthy volunteer median, with two below the 5th percentile (rank-sum p = 0.018; Fisher p = 0.045).\n\nConclusionsRegional 7T 3{superscript 1}P-MRSI detects segment-level energetic differences across cardiovascular disease states and reveals spatially specific energetic-mechanical coupling confined to the septal segments in the current ungated acquisition. Energetic impairment in ischaemic cardiomyopathy extends into structurally preserved remote myocardium. These findings support larger studies using regional 3{superscript 1}P-MRSI to investigate regional energetic-mechanical coupling as a target for metabolic cardiac therapies.",
  "abstract_shown": true,
  "affiliations": [
    "Wolfson Brain Imaging Center"
  ],
  "article_type": "PUBLISHAHEADOFPRINT",
  "arxiv": null,
  "author_total": 9,
  "authors": [
    {
      "affs": [
        0
      ],
      "name": "J. Karkouri"
    },
    {
      "name": "W. Watson"
    },
    {
      "name": "T. Horn"
    },
    {
      "name": "M. Hill"
    },
    {
      "name": "D. Klomp"
    },
    {
      "name": "M. Mallouppas"
    },
    {
      "name": "C. Bhagra"
    },
    {
      "name": "S. Hoole"
    },
    {
      "name": "C. Rodgers"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/fbt5m501jkbj3.bib",
  "cited_by": 0,
  "doi": "10.64898/2026.09.04.26362251",
  "fulltext_url": "https://www.medrxiv.org/content/10.64898/2026.09.04.26362251v1.full",
  "id": "fbt5m501jkbj3",
  "issns": [],
  "landing_url": "https://www.medrxiv.org/content/10.64898/2026.09.04.26362251v1",
  "language": null,
  "licence": "CC-BY-ND",
  "licence_label": "CC BY-ND",
  "licence_source": "article",
  "licence_url": "https://creativecommons.org/licenses/by-nd/4.0/",
  "metadata_licence": null,
  "native_subjects": [
    [
      "medrxiv",
      "cardiovascular medicine"
    ],
    [
      "openalex",
      "2741|Advanced MRI Techniques and Applications"
    ]
  ],
  "openalex": "W7212084250",
  "pdf_url": "https://www.medrxiv.org/content/10.64898/2026.09.04.26362251v1.full.pdf",
  "pmcid": null,
  "pmid": null,
  "published": "2026-09-04",
  "publisher": null,
  "ris": "https://research.draconitic.com/paper/fbt5m501jkbj3.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:18:11Z",
      "native_id": "10.64898/2026.09.04.26362251",
      "source": "medrxiv",
      "url": "https://www.medrxiv.org/content/10.64898/2026.09.04.26362251v1"
    }
  ],
  "subjects": [
    {
      "field": "medicine",
      "origin": "medrxiv:cardiovascular medicine",
      "subfield": "cardiovascular"
    }
  ],
  "title": "Regional cardiac 31P-MRSI at 7T: detection of spatially heterogeneous patterns of myocardial energetic impairment",
  "title_text": "Regional cardiac 31P-MRSI at 7T: detection of spatially heterogeneous patterns of myocardial energetic impairment",
  "type": "preprint",
  "updated_at": "2026-10-30T12:18:11Z",
  "url": "https://research.draconitic.com/paper/fbt5m501jkbj3",
  "venue": "medRxiv",
  "versions": []
}