{ "abstract": "Background: Serial ultrasound measurements may help characterize muscle wasting in critically ill patients. The flexor carpi ulnaris (FCU) is a superficial forearm muscle that may provide an additional assessment site. We described longitudinal FCU and biceps brachii (BB) cross-sectional area (CSA) changes and explored between-muscle differences and clinical associations. Methods: This prospective two-center observational study enrolled 23 intensive care unit (ICU) patients; 20 were included in the analysis (median age, 57 years; range, 33–82). CSA was measured on days 0, 5, 7, and 14 after ICU admission. Analyses used Friedman tests, exact conditional Wilcoxon signed-rank tests with Bonferroni correction, and exploratory Spearman correlations. Post hoc between-muscle comparisons assessed participant-level percentage changes. Results: Mean FCU CSA decreased from 1.36 to 1.08 cm² and mean BB CSA from 6.08 to 5.09 cm² over 14 days, corresponding to reductions of 20.9% and 16.4% in the unrounded group means. The median paired difference in percentage change (FCU minus BB) was −11.9 percentage points on day 7 (unadjusted p = 0.0023), meeting the Bonferroni threshold of 0.05/3. Differences on days 5 and 14 did not meet this threshold (p = 0.1429 and p = 0.2024). Baseline CSA values were correlated (ρ = 0.845, p < 0.001), as were 14-day percentage changes (ρ = 0.549, p = 0.0122); correlation p-values were unadjusted. Conclusions: Serial ultrasound documented decreases in FCU and BB CSA in this small cohort, with an exploratory direct comparison identifying a greater proportional FCU decrease on day 7. These findings support further evaluation of FCU ultrasound as an additional muscle-monitoring measure. Its value for earlier detection of muscle wasting or diagnosis of ICU-acquired weakness requires direct validation.", "abstract_shown": true, "affiliations": [ "Department of Occupational Therapy, School of Rehabilitation, Tokyo Professional University of Health Sciences, Koto-ku, Tokyo, Japan.", "Division of Occupational Therapy, Department of Rehabilitation, School of Nursing and Rehabilitation Sciences, Showa Medical University, Midori-ku, Kanagawa, Japan.", "Department of Rehabilitation Medicine, Showa Medical University, School of Medicine, Shinagawa-ku, Tokyo, Japan.", "Division of Morphology, Anatomy and Physiology, Department of Medical Basics, Specialty and Education, Showa Medical University, Graduate School of Nursing and Rehabilitation Sciences, Midori-ku, Kanagawa, Japan.", "Department of Physical Therapy, Faculty of Rehabilitation, Gunma Paz University, Takasaki-shi, Japan.", "Division of Cardiopulmonary Rehabilitation Science, Department of Rehabilitation, Showa Medical University, Graduate School of Nursing and Rehabilitation Sciences, Midori-ku, Kanagawa, Japan." ], "article_type": "Research Article", "arxiv": null, "author_total": 9, "authors": [ { "affs": [ 0, 1 ], "name": "Keiichiro Aoki", "orcid": "0009-0000-0338-2372" }, { "affs": [ 2 ], "name": "Fumihito Kasai" }, { "affs": [ 1 ], "name": "Kazuki Komaba" }, { "affs": [ 1 ], "name": "Jin Saito" }, { "affs": [ 3 ], "name": "Akira Yoshikawa", "orcid": "0000-0002-4424-1629" }, { "affs": [ 4 ], "name": "Naonori Tashiro" }, { "affs": [ 5 ], "name": "Hiroyasu Inoue", "orcid": "0009-0001-4376-9675" }, { "affs": [ 1 ], "name": "Kengo Uchibori" }, { "affs": [ 2 ], "name": "Miwa Fukazawa" } ], "bibtex": "https://research.draconitic.com/paper/fc71pb2f8sejp.bib", "cited_by": 0, "doi": "10.1371/journal.pone.0361123", "fulltext_url": "https://europepmc.org/articles/PMC13718933", "id": "fc71pb2f8sejp", "issns": [ "1932-6203" ], "landing_url": "https://doi.org/10.1371/journal.pone.0361123", "language": "eng", "licence": "CC-BY", "licence_label": "CC BY", "licence_source": "article", "licence_url": "https://creativecommons.org/licenses/by/4.0/", "metadata_licence": null, "native_subjects": [ [ "heading", "Anatomy" ], [ "heading", "Arms" ], [ "heading", "Bioassays and Physiological Analysis" ], [ "heading", "Biology and Life Sciences" ], [ "heading", "Body Limbs" ], [ "heading", "Diagnostic Medicine" ], [ "heading", "Diagnostic Radiology" ], [ "heading", "Elbow" ], [ "heading", "Forearms" ], [ "heading", "Health Care" ], [ "heading", "Health Care Facilities" ], [ "heading", "Hospitals" ], [ "heading", "Imaging Techniques" ], [ "heading", "Intensive Care Units" ], [ "heading", "Medicine and Health Sciences" ], [ "heading", "Muscle Analysis" ], [ "heading", "Muscle Functions" ], [ "heading", "Muscle Physiology" ], [ "heading", "Muscles" ], [ "heading", "Musculoskeletal System" ], [ "heading", "Observational Studies" ], [ "heading", "Physiology" ], [ "heading", "Radiology and Imaging" ], [ "heading", "Research Article" ], [ "heading", "Research Design" ], [ "heading", "Research and Analysis Methods" ], [ "heading", "Skeletal Muscles" ], [ "heading", "Ultrasound Imaging" ], [ "plos", "/Biology and life sciences/Anatomy/Body limbs/Arms/Elbow" ], [ "plos", "/Biology and life sciences/Anatomy/Body limbs/Arms/Forearms" ], [ "plos", "/Biology and life sciences/Anatomy/Musculoskeletal system/Muscles/Skeletal muscles" ], [ "plos", "/Biology and life sciences/Physiology/Muscle physiology/Muscle functions" ], [ "plos", "/Medicine and health sciences/Anatomy/Body limbs/Arms/Elbow" ], [ "plos", "/Medicine and health sciences/Anatomy/Body limbs/Arms/Forearms" ], [ "plos", "/Medicine and health sciences/Anatomy/Musculoskeletal system/Muscles/Skeletal muscles" ], [ "plos", "/Medicine and health sciences/Diagnostic medicine/Diagnostic radiology/Ultrasound imaging" ], [ "plos", "/Medicine and health sciences/Health care/Health care facilities/Hospitals/Intensive care units" ], [ "plos", "/Medicine and health sciences/Radiology and imaging/Diagnostic radiology/Ultrasound imaging" ], [ "plos", "/Research and analysis methods/Bioassays and physiological analysis/Muscle analysis" ], [ "plos", "/Research and analysis methods/Imaging techniques/Diagnostic radiology/Ultrasound imaging" ], [ "plos", "/Research and analysis methods/Research design/Observational studies" ] ], "openalex": null, "pdf_url": "https://europepmc.org/articles/PMC13718933?pdf=render", "pmcid": "PMC13718933", "pmid": "42956012", "published": "2026-10-29", "publisher": "Public Library of Science", "ris": "https://research.draconitic.com/paper/fc71pb2f8sejp.ris", "sources": [ { "first_seen": "2026-10-30T12:17:17Z", "native_id": "10.1371/journal.pone.0361123", "source": "plos", "url": "https://doi.org/10.1371/journal.pone.0361123" }, { "first_seen": "2026-11-01T00:20:36Z", "native_id": "MED:42956012", "source": "europepmc", "url": "https://europepmc.org/article/MED/42956012" }, { "first_seen": "2026-11-02T12:22:52Z", "native_id": "PMC13718933", "source": "pmc", "url": "https://doi.org/10.1371/journal.pone.0361123" } ], "subjects": [ { "field": "biology", "origin": "heading:Biology and Life Sciences", "subfield": "general" }, { "field": "medicine", "origin": "heading:Diagnostic Radiology", "subfield": "imaging" }, { "field": "medicine", "origin": "plos:anatomy", "subfield": "physiology" } ], "title": "Serial ultrasound assessment of flexor carpi ulnaris and biceps brachii cross-sectional area in critically ill patients: A prospective cohort study", "title_text": "Serial ultrasound assessment of flexor carpi ulnaris and biceps brachii cross-sectional area in critically ill patients: A prospective cohort study", "type": "peer-reviewed", "updated_at": "2026-11-02T12:22:52Z", "url": "https://research.draconitic.com/paper/fc71pb2f8sejp", "venue": "PLOS One", "versions": [] }