Effect of Aortic Arch Position on the Bronchial Length Ratio

Effect of Aortic Arch Position on the Bronchial Length Ratio | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Research Article Effect of Aortic Arch Position on the Bronchial Length Ratio Chae Young Kim, Romina D’Souza, Afsaneh Amirabadi, J. A. Gordon Culham, and 1 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-7330144/v1 This work is licensed under a CC BY 4.0 License Status: Posted Version 1 posted You are reading this latest preprint version Abstract Background Bronchial length ratio (BLR) is widely used to differentiate heterotaxy with right or left isomerism from situs solitus or inversus. During daily experience, we found that the bronchial length is also affected by the position of the aortic arch and wondered whether the bronchial length ratio is a reliable indicator of the thoracic situs. Objective To examine the influence of the position of the aortic arch on the BLR and assess the accuracy of the BLR in defining the body situs. Material and Methods The study population was selected from the radiologic database of 2001–2022 using the key words, left aortic arch, right aortic arch, double aortic arch, situs inversus, heterotaxy and isomerism. From the patients identified, the patients having good quality computed tomographic angiograms (CTA) or magnetic resonance angiograms (MRA) were chosen. Using a 3D workstation, the lengths of the main bronchi were measured and the ratio between the longer and shorter bronchi was calculated. The relationship between the main bronchi and the branch pulmonary arteries and the position of the aortic arch relative to the trachea was recorded. The BLR and the broncho-pulmonary arterial relationship were compared among the groups having different combinations of body situs and aortic arch position. Results The study population consisted of 69 patients with situs solitus and left aortic arch (Group 1A), 20 with situs inversus and right aortic arch (Group 1B), 43 with situs solitus and right aortic arch (Group 2A), 2 with situs inversus and left aortic arch (Group 2B), 11 with situs solitus and double aortic arch (Group 3), and 14 with heterotaxy with right or left isomerism (Group 4). Group 2 (2A + 2B) showed a significantly smaller BLR than Group 1 (1A + 1B) ( p = 0.001). Group 3 also showed a smaller BLR than Group 1 but without statistical significance ( p = 0.26). Group 4 showed a significantly smaller BLR than Groups 1–3 ( p < 0.001). In Group 1, there was no patient having the BLR fall in the range of heterotaxy group (Group 4). In Group 2, 5 patients (11%) had BLR within the range of heterotaxy group. In Group 3, one patient (9%) had BLR within the range of heterotaxy group. In all patients, the broncho-pulmonary arterial relationship was consistent with the situs of the rest of the body. Conclusion The BLR is affected by the position of the aortic arch. The ratio is smaller when the aortic arch is in an unusual position for the given situs, for example, right or double aortic arch in situs solitus and left aortic arch in situs inversus, than when the aortic arch is in a usual position. Therefore, the BLR is of limited value in situs determination. The broncho-pulmonary arterial relationship should be used as the primary criterion for situs determination. Full Text Additional Declarations No competing interests reported. Cite Share Download PDF Status: Posted Version 1 posted You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. We do this by developing innovative software and high quality services for the global research community. Our growing team is made up of researchers and industry professionals working together to solve the most critical problems facing scientific publishing. Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-7330144","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":501515438,"identity":"2b4e07c1-c659-44c1-add0-56a7c86e2204","order_by":0,"name":"Chae Young Kim","email":"","orcid":"","institution":"Hospital for Sick Children, University of Toronto","correspondingAuthor":false,"prefix":"","firstName":"Chae","middleName":"Young","lastName":"Kim","suffix":""},{"id":501515439,"identity":"48b8149f-5bdd-4d70-a18b-a70aaba160ad","order_by":1,"name":"Romina D’Souza","email":"","orcid":"","institution":"Hospital for Sick Children, University of Toronto","correspondingAuthor":false,"prefix":"","firstName":"Romina","middleName":"","lastName":"D’Souza","suffix":""},{"id":501515441,"identity":"79c18932-e754-4de1-8385-ad15fca477e3","order_by":2,"name":"Afsaneh Amirabadi","email":"","orcid":"","institution":"Hospital for Sick Children, University of Toronto","correspondingAuthor":false,"prefix":"","firstName":"Afsaneh","middleName":"","lastName":"Amirabadi","suffix":""},{"id":501515443,"identity":"5a0d7de8-34c2-40d1-8c86-b86512a5bbdd","order_by":3,"name":"J. 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During daily experience, we found that the bronchial length is also affected by the position of the aortic arch and wondered whether the bronchial length ratio is a reliable indicator of the thoracic situs.\u003c/p\u003e\u003ch2\u003eObjective\u003c/h2\u003e\u003cp\u003eTo examine the influence of the position of the aortic arch on the BLR and assess the accuracy of the BLR in defining the body situs.\u003c/p\u003e\u003ch2\u003eMaterial and Methods\u003c/h2\u003e\u003cp\u003eThe study population was selected from the radiologic database of 2001\u0026ndash;2022 using the key words, left aortic arch, right aortic arch, double aortic arch, situs inversus, heterotaxy and isomerism. From the patients identified, the patients having good quality computed tomographic angiograms (CTA) or magnetic resonance angiograms (MRA) were chosen. Using a 3D workstation, the lengths of the main bronchi were measured and the ratio between the longer and shorter bronchi was calculated. The relationship between the main bronchi and the branch pulmonary arteries and the position of the aortic arch relative to the trachea was recorded. The BLR and the broncho-pulmonary arterial relationship were compared among the groups having different combinations of body situs and aortic arch position.\u003c/p\u003e\u003ch2\u003eResults\u003c/h2\u003e\u003cp\u003eThe study population consisted of 69 patients with situs solitus and left aortic arch (Group 1A), 20 with situs inversus and right aortic arch (Group 1B), 43 with situs solitus and right aortic arch (Group 2A), 2 with situs inversus and left aortic arch (Group 2B), 11 with situs solitus and double aortic arch (Group 3), and 14 with heterotaxy with right or left isomerism (Group 4). Group 2 (2A\u0026thinsp;+\u0026thinsp;2B) showed a significantly smaller BLR than Group 1 (1A\u0026thinsp;+\u0026thinsp;1B) (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.001). Group 3 also showed a smaller BLR than Group 1 but without statistical significance (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.26). Group 4 showed a significantly smaller BLR than Groups 1\u0026ndash;3 (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.001). In Group 1, there was no patient having the BLR fall in the range of heterotaxy group (Group 4). In Group 2, 5 patients (11%) had BLR within the range of heterotaxy group. In Group 3, one patient (9%) had BLR within the range of heterotaxy group. In all patients, the broncho-pulmonary arterial relationship was consistent with the situs of the rest of the body.\u003c/p\u003e\u003ch2\u003eConclusion\u003c/h2\u003e\u003cp\u003eThe BLR is affected by the position of the aortic arch. The ratio is smaller when the aortic arch is in an unusual position for the given situs, for example, right or double aortic arch in situs solitus and left aortic arch in situs inversus, than when the aortic arch is in a usual position. Therefore, the BLR is of limited value in situs determination. The broncho-pulmonary arterial relationship should be used as the primary criterion for situs determination.\u003c/p\u003e","manuscriptTitle":"Effect of Aortic Arch Position on the Bronchial Length Ratio","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-08-19 18:51:26","doi":"10.21203/rs.3.rs-7330144/v1","editorialEvents":[{"type":"communityComments","content":0}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"a41d7e73-ad1e-4f2a-959f-8a9b627918f6","owner":[],"postedDate":"August 19th, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[],"tags":[],"updatedAt":"2025-09-16T18:53:26+00:00","versionOfRecord":[],"versionCreatedAt":"2025-08-19 18:51:26","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-7330144","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-7330144","identity":"rs-7330144","version":["v1"]},"buildId":"8U1c8b4HqxoKbykW_rLl7","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}