{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,10,20]],"date-time":"2026-10-20T21:41:28Z","timestamp":1792532488136,"version":"4.5.0"},"reference-count":40,"publisher":"MDPI AG","issue":"2","license":[{"start":{"date-parts":[[2026,1,12]],"date-time":"2026-01-12T00:00:00Z","timestamp":1768176000000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"Songcheon Medical Research Fund of Sungkyunkwan University"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["JCM"],"abstract":"<jats:p>Background\/Objectives: This study evaluated the validity of DEXA-derived muscle quantification by assessing its agreement with AI-assisted CT measurements of muscle volume and intramuscular adipose tissue. It also examined whether inter-limb asymmetry improves DEXA\u2013CT agreement beyond absolute DEXA values. The influence of lower-limb rotation on DEXA measurements was assessed, and the study aimed to clarify how DEXA should be obtained and interpreted to more accurately reflect true muscle status. Methods: Fifty-two patients who completed CT and DEXA within 14 days were included. CT was used to obtain pure muscle volume and intramuscular adipose tissue (IMAT) using a standardized AI segmentation protocol, and corresponding DEXA thigh segmentation provided lean mass and fat percentage. Position-specific correlation analysis, regression, and Bland\u2013Altman agreement testing were performed for 104 limbs. The same analyses were applied to inter-limb differences to isolate within-person asymmetry and reduce between-person variance. Results: DEXA lean mass correlated with CT pure muscle volume (r = 0.776, p &lt; 0.001), and inter-limb asymmetry further improved alignment with CT (r = 0.857, p &lt; 0.001). However, DEXA fat mass asymmetry demonstrated no association with CT IMAT asymmetry (r = \u22120.004, p = 0.979). When results were stratified by the recorded rotational groups, the highest correlation was observed in the neutral position (r = 0.900, p &lt; 0.001). Bland\u2013Altman analyses showed wide limits of agreement for all absolute measurements, whereas inter-limb asymmetry demonstrated markedly narrower limits of agreement, indicating superior numerical consistency. Conclusions: Absolute DEXA estimates showed limited agreement with CT and varied with limb position. Inter-limb asymmetry improved lean mass assessment, whereas fat mass and percentage did not correspond to CT-based IMAT. DEXA may therefore be used as a complementary tool for evaluating regional muscle quantity, but not for assessing muscle quality.<\/jats:p>","DOI":"10.3390\/jcm15020594","type":"journal-article","created":{"date-parts":[[2026,1,12]],"date-time":"2026-01-12T09:13:01Z","timestamp":1768209181000},"page":"594","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":1,"title":["Validity of DEXA-Derived Thigh Muscle Quantification Against AI-Assisted CT: Inter-Limb Asymmetry Provides Superior Agreement over Absolute Values"],"prefix":"10.3390","volume":"15","author":[{"ORCID":"https:\/\/orcid.org\/0000-0001-6596-1222","authenticated-orcid":false,"given":"Do Kyung","family":"Lee","sequence":"first","affiliation":[{"name":"Department of Orthopedic Surgery, Samsung Changwon Hospital, Sungkyunkwan University School of Medicine, Changwon 51353, Republic of Korea"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2026,1,12]]},"reference":[{"key":"ref_1","first-page":"221","article-title":"Why muscle strengthening exercises should target the quadriceps and gluteus maximus in patients with knee osteoarthritis?: Effects of knee pain on muscle volume and fatty degeneration based on AI-assisted cross-sectional analysis","volume":"53","author":"Lee","year":"2025","journal-title":"J. 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