{
  "abstract": "PurposeUltrasound time-harmonic elastography (THE) uses continuous multifrequency vibration and standard-frame-rate ultrasound to generate full-field mechanical maps. We tested whether THE concurrently resolves task-dependent responses in the thin thoracolumbar fascia (TLF) and deeper multifidus muscle (MFM) during back extension.\n\nMethodsEighteen healthy adults (9 female and 9 male; age 19.4 {+/-} 1.9 years) underwent multifrequency THE (60-80 Hz; 100 frames/s) at rest and during active back extension. Shear wave speed (SWS) and penetration rate (PR), an attenuation-sensitive measure, were quantified in manually defined TLF and MFM regions. Four within-tissue contrasts were tested using paired t tests with Holm adjustment; between-tissue, superficial-tissue-thickness, and sex analyses were exploratory.\n\nResultsBack extension increased SWS in the TLF (+0.43 {+/-} 0.43 m/s; dz = 0.99) and MFM (+0.62 {+/-} 0.23 m/s; dz = 2.73) and decreased PR in the TLF (-1.01 {+/-} 0.54 m/s; dz = -1.88) and MFM (-1.20 {+/-} 0.51 m/s; dz = -2.34); all Holm-adjusted p < 0.001. The SWS increase was 0.19 m/s greater in MFM than TLF (95% confidence interval, 0.01-0.38 m/s; unadjusted p = 0.042), whereas PR changes did not differ between tissues (p = 0.233).\n\nConclusionTHE simultaneously captured spatially resolved, task-dependent responses in adjacent fascial and muscle tissues using standard-frame-rate acquisition. The findings establish biomechanical sensitivity in healthy adults and support further validation with standardized loading, repeatability testing, and comparison with conventional shear wave elastography.\n\nClinical trial numbernot applicable.",
  "abstract_shown": true,
  "affiliations": [
    "Charite-Universitatsmedizin Berlin"
  ],
  "article_type": "PUBLISHAHEADOFPRINT",
  "arxiv": null,
  "author_total": 6,
  "authors": [
    {
      "name": "E. Kurz"
    },
    {
      "name": "T. Meyer"
    },
    {
      "name": "R. Schwesig"
    },
    {
      "name": "S. Delank"
    },
    {
      "name": "I. Sack"
    },
    {
      "affs": [
        0
      ],
      "name": "H. S. Aghamiry"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/dvsyzx90xebjj.bib",
  "cited_by": 0,
  "doi": "10.64898/2026.09.17.26363289",
  "fulltext_url": "https://www.medrxiv.org/content/10.64898/2026.09.17.26363289v1.full",
  "id": "dvsyzx90xebjj",
  "issns": [],
  "landing_url": "https://www.medrxiv.org/content/10.64898/2026.09.17.26363289v1",
  "language": null,
  "licence": "CC-BY-NC",
  "licence_label": "CC BY-NC",
  "licence_source": "article",
  "licence_url": "https://creativecommons.org/licenses/by-nc/4.0/",
  "metadata_licence": null,
  "native_subjects": [
    [
      "medrxiv",
      "radiology and imaging"
    ],
    [
      "openalex",
      "2741|Ultrasound Imaging and Elastography"
    ]
  ],
  "openalex": "W7213792407",
  "pdf_url": "https://www.medrxiv.org/content/10.64898/2026.09.17.26363289v1.full.pdf",
  "pmcid": null,
  "pmid": null,
  "published": "2026-09-17",
  "publisher": null,
  "ris": "https://research.draconitic.com/paper/dvsyzx90xebjj.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:18:58Z",
      "native_id": "10.64898/2026.09.17.26363289",
      "source": "medrxiv",
      "url": "https://www.medrxiv.org/content/10.64898/2026.09.17.26363289v1"
    }
  ],
  "subjects": [
    {
      "field": "medicine",
      "origin": "medrxiv:radiology and imaging",
      "subfield": "imaging"
    }
  ],
  "title": "Full-Field Ultrasound Time-Harmonic Elastography Quantifies Task-Dependent Thoracolumbar Fascia and Multifidus Mechanics During Back Extension",
  "title_text": "Full-Field Ultrasound Time-Harmonic Elastography Quantifies Task-Dependent Thoracolumbar Fascia and Multifidus Mechanics During Back Extension",
  "type": "preprint",
  "updated_at": "2026-10-30T12:18:58Z",
  "url": "https://research.draconitic.com/paper/dvsyzx90xebjj",
  "venue": "medRxiv",
  "versions": []
}