{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,8,19]],"date-time":"2026-08-19T14:33:21Z","timestamp":1787150001077,"version":"build-2736575974"},"reference-count":52,"publisher":"MDPI AG","issue":"16","license":[{"start":{"date-parts":[[2026,8,19]],"date-time":"2026-08-19T00:00:00Z","timestamp":1787097600000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Diagnostics"],"abstract":"<jats:p>Background\/Objectives: CT-based trabecular attenuation in Hounsfield units (HU) is used as a surrogate marker of bone quality, but most approaches rely on a single vertebral level, usually L1, where local abnormalities may limit reliability and availability. This study evaluated whether multilevel lumbar, reference-adjusted HU assessment beyond isolated L1 improves the identification of QCT-defined osteoporosis and the discrimination of prevalent fragility fracture status. Methods: Between 2021 and March 2024, 800 patients referred for evaluation of bone mineral density underwent QCT of the lumbar spine with a calibration phantom. Cancellous attenuation was measured in HU at L1\u2013L3 using manually positioned ellipsoid regions of interest, with predefined adjacent levels (T12, L4) substituted when a target vertebra was unsuitable. Single-level HU, the mean multilevel HU value and the lowest valid HU value were compared with QCT-defined osteoporosis and prevalent fragility fracture status (vertebral or sacral) using ROC analyses and pairwise DeLong testing. Results: Mean multilevel HU correlated closely with mean vBMD (Spearman \u03c1 = 0.988; p &lt; 0.001); as both derive from the same acquisition, the same vertebral bodies and the same phantom, this reflects a strong association between two related measurements rather than validation against an independent standard. Osteoporosis was present in 483 patients (60.4%). Mean multilevel HU was associated with osteoporosis with an AUC of 0.996 (95% CI, 0.993\u20130.998) at an internally derived cut-off of \u226499.6 HU. In the 699 patients with a valid L1 measurement, in whom a paired comparison was possible, mean multilevel HU exceeded isolated L1-HU (0.992; p = 0.0028). For fracture status, the AUC was 0.975 (0.966\u20130.983) at \u226480.5 HU, without advantage over L1-HU (p = 0.816). A valid value was obtainable in all 800 patients versus 699 (87.4%) with L1 alone. All patients with a fracture had a vBMD below the osteoporosis threshold, so this endpoint is structurally dependent on the densitometric one. Conclusions: Multilevel lumbar HU assessment provides a practical marker of trabecular bone quality beyond isolated L1. Its principal advantage is measurement availability rather than a clinically meaningful gain in discrimination. The reported thresholds are internally derived, cohort- and protocol-specific, and require external validation.<\/jats:p>","DOI":"10.3390\/diagnostics16162640","type":"journal-article","created":{"date-parts":[[2026,8,19]],"date-time":"2026-08-19T14:07:34Z","timestamp":1787148454000},"page":"2640","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["Multilevel Lumbar CT Attenuation Beyond L1: Comparison with QCT-Derived Volumetric Bone Mineral Density and Prevalent Fragility Fracture Status in a Diagnostic Referral Cohort"],"prefix":"10.3390","volume":"16","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-1385-2793","authenticated-orcid":false,"given":"Julian Ramin","family":"Andresen","sequence":"first","affiliation":[{"name":"Department of Orthopaedics, University Clinic for Orthopaedics and Trauma Surgery, Medical University of Vienna, Waehringer Guertel 18-20, 1090 Vienna, Austria"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Stephan","family":"Heisinger","sequence":"additional","affiliation":[{"name":"Department of Trauma Surgery, University Clinic for Orthopaedics and Trauma Surgery, Medical University of Vienna, Waehringer Guertel 18-20, 1090 Vienna, Austria"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-3192-8453","authenticated-orcid":false,"given":"Thomas","family":"Haider","sequence":"additional","affiliation":[{"name":"Department of Trauma Surgery, University Clinic for Orthopaedics and Trauma Surgery, Medical University of Vienna, Waehringer Guertel 18-20, 1090 Vienna, Austria"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Hans-Christof","family":"Schober","sequence":"additional","affiliation":[{"name":"Practice for Orthopedics and Osteology, OrthoCoast, Hufelandstrasse 1, 17438 Wolgast, Germany"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-1575-525X","authenticated-orcid":false,"given":"Reimer","family":"Andresen","sequence":"additional","affiliation":[{"name":"Institute for Diagnostic and Interventional Radiology\/Neuroradiology, Westkuestenklinikum Heide, Academic Teaching Hospital of the Universities of Kiel, Luebeck and Hamburg, Esmarchstrasse 50, 25746 Heide, Germany"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2026,8,19]]},"reference":[{"key":"ref_1","first-page":"46","article-title":"An overview and management of osteoporosis","volume":"4","year":"2017","journal-title":"Eur. 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Med., 13.","DOI":"10.3389\/fmed.2026.1779483"}],"container-title":["Diagnostics"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/2075-4418\/16\/16\/2640\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2026,8,19]],"date-time":"2026-08-19T14:12:09Z","timestamp":1787148729000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/2075-4418\/16\/16\/2640"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2026,8,19]]},"references-count":52,"journal-issue":{"issue":"16","published-online":{"date-parts":[[2026,8]]}},"alternative-id":["diagnostics16162640"],"URL":"https:\/\/doi.org\/10.3390\/diagnostics16162640","relation":{},"ISSN":["2075-4418"],"issn-type":[{"value":"2075-4418","type":"electronic"}],"subject":[],"published":{"date-parts":[[2026,8,19]]}}}