{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,2,27]],"date-time":"2026-02-27T02:47:51Z","timestamp":1772160471696,"version":"3.50.1"},"reference-count":34,"publisher":"Springer Science and Business Media LLC","issue":"1","license":[{"start":{"date-parts":[[2024,7,11]],"date-time":"2024-07-11T00:00:00Z","timestamp":1720656000000},"content-version":"tdm","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0"},{"start":{"date-parts":[[2024,7,11]],"date-time":"2024-07-11T00:00:00Z","timestamp":1720656000000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0"}],"content-domain":{"domain":["link.springer.com"],"crossmark-restriction":false},"short-container-title":["Eur Radiol"],"abstract":"<jats:title>Abstract<\/jats:title><jats:sec>\n                <jats:title>Objectives<\/jats:title>\n                <jats:p>The aim of this study was to introduce the blackbird sign as a fast, qualitative measure of early supraspinatus (SSP) muscle atrophy and to correlate the sign with quantitatively assessed muscle volume and intramuscular fat fraction (FF) in patients with full-thickness SSP tears.<\/jats:p>\n              <\/jats:sec><jats:sec>\n                <jats:title>Materials and methods<\/jats:title>\n                <jats:p>The blackbird sign describes the asymmetric pattern of early SSP atrophy: on sagittal MR images, the supero\u2013posterior contour of the muscle becomes concave, resembling the shape of a blackbird. MRIs of patients with full-thickness SSP tears were retrospectively reviewed for the presence of the blackbird and tangent signs. Patients were then divided into group 1: negative tangent sign and negative blackbird sign (<jats:italic>n<\/jats:italic>\u2009=\u200967), group 2: negative tangent sign and positive blackbird sign (<jats:italic>n<\/jats:italic>\u2009=\u200931), and group 3: positive tangent sign (<jats:italic>n<\/jats:italic>\u2009=\u200932). A 2-point Dixon sequence was acquired in all patients from which quantitative FF and muscle volumes were calculated.<\/jats:p>\n              <\/jats:sec><jats:sec>\n                <jats:title>Results<\/jats:title>\n                <jats:p>In total 130 patients (mean age 67\u2009\u00b1\u200911 years) were included. Mean SSP volume was significantly smaller in group 3 (15.8\u2009\u00b1\u20098.1\u2009cm<jats:sup>3<\/jats:sup>) compared to group 2 (23.9\u2009\u00b1\u20097.0\u2009cm<jats:sup>3<\/jats:sup>, <jats:italic>p<\/jats:italic>\u2009=\u20090.01) and group 1 (29.7\u2009\u00b1\u20099.1\u2009cm<jats:sup>3<\/jats:sup>, <jats:italic>p<\/jats:italic>\u2009&lt;\u20090.01). Significantly lower muscle volumes were also found in group 2 compared to group 1 (<jats:italic>p<\/jats:italic>\u2009=\u20090.02), confirming that the blackbird sign is able to identify early SSP atrophy. Mean FF in the SSP was significantly higher in group 3 (18.5\u2009\u00b1\u20094.4%) compared to group 2 (10.9\u2009\u00b1\u20094.7%, <jats:italic>p<\/jats:italic>\u2009&lt;\u20090.01) and group 1 (6.1\u2009\u00b1\u20092.6%, <jats:italic>p<\/jats:italic>\u2009&lt;\u20090.01).<\/jats:p>\n              <\/jats:sec><jats:sec>\n                <jats:title>Conclusion<\/jats:title>\n                <jats:p>Visual assessment of early muscle atrophy of the SSP is feasible and reproducible using the blackbird sign, allowing the diagnosis of early SSP atrophy.<\/jats:p>\n              <\/jats:sec><jats:sec>\n                <jats:title>Clinical relevance statement<\/jats:title>\n                <jats:p>In routine clinical practice, the blackbird sign may be a useful tool for assessing early muscle degeneration before the risk of postoperative rotator cuff re-tears increases with progressive muscle atrophy and fatty infiltration.<\/jats:p>\n              <\/jats:sec><jats:sec>\n                <jats:title>Key Points<\/jats:title>\n                <jats:p><jats:list list-type=\"bullet\">\n                  <jats:list-item>\n                    <jats:p><jats:italic>Quantitative measurements of rotator cuff injuries require time, limiting clinical practicality<\/jats:italic>.<\/jats:p>\n                  <\/jats:list-item>\n                  <jats:list-item>\n                    <jats:p><jats:italic>The proposed blackbird sign is able to identify early SSP atrophy<\/jats:italic>.<\/jats:p>\n                  <\/jats:list-item>\n                  <jats:list-item>\n                    <jats:p><jats:italic>Reader agreement for the blackbird sign was substantial, demonstrating reproducibility and ease of implementation in the clinical routine<\/jats:italic>.<\/jats:p>\n                  <\/jats:list-item>\n                <\/jats:list><\/jats:p>\n              <\/jats:sec>","DOI":"10.1007\/s00330-024-10946-7","type":"journal-article","created":{"date-parts":[[2024,7,11]],"date-time":"2024-07-11T17:01:29Z","timestamp":1720717289000},"page":"313-322","update-policy":"https:\/\/doi.org\/10.1007\/springer_crossmark_policy","source":"Crossref","is-referenced-by-count":4,"title":["A visual marker for early atrophy of the supraspinatus muscle on conventional MRI: introduction of the blackbird sign"],"prefix":"10.1007","volume":"35","author":[{"ORCID":"https:\/\/orcid.org\/0000-0001-5313-5011","authenticated-orcid":false,"given":"Georg C.","family":"Feuerriegel","sequence":"first","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Roy P.","family":"Marcus","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Sophia S.","family":"Goller","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Adrian A.","family":"Marth","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Karl","family":"Wieser","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Samy","family":"Bouaicha","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Reto","family":"Sutter","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"297","published-online":{"date-parts":[[2024,7,11]]},"reference":[{"key":"10946_CR1","doi-asserted-by":"publisher","first-page":"2764","DOI":"10.2106\/00004623-200412000-00027","volume":"86","author":"GR Williams Jr","year":"2004","unstructured":"Williams GR Jr, Rockwood CA Jr, Bigliani LU et al (2004) Rotator cuff tears: Why do we repair them? 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Feuerriegel.","order":2,"name":"Ethics","group":{"name":"EthicsHeading","label":"Guarantor"}},{"value":"Balgrist University Hospital has an academic research agreement with Siemens Healthineers.","order":3,"name":"Ethics","group":{"name":"EthicsHeading","label":"Conflict of interest"}},{"value":"No complex statistical methods were necessary for this paper.","order":4,"name":"Ethics","group":{"name":"EthicsHeading","label":"Statistics and biometry"}},{"value":"Written informed consent was obtained from all subjects (patients) in this study.","order":5,"name":"Ethics","group":{"name":"EthicsHeading","label":"Informed consent"}},{"value":"Institutional Review Board approval was obtained.","order":6,"name":"Ethics","group":{"name":"EthicsHeading","label":"Ethical approval"}},{"value":"None.","order":7,"name":"Ethics","group":{"name":"EthicsHeading","label":"Study subjects or cohorts overlap"}},{"order":8,"name":"Ethics","group":{"name":"EthicsHeading","label":"Methodology"}}]}}