{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,8,28]],"date-time":"2026-08-28T19:29:21Z","timestamp":1787945361293,"version":"build-2784847793"},"reference-count":18,"publisher":"MDPI AG","issue":"17","license":[{"start":{"date-parts":[[2025,9,7]],"date-time":"2025-09-07T00:00:00Z","timestamp":1757203200000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"Mackay Memorial Hospital","award":["MMH-TT-112-03"],"award-info":[{"award-number":["MMH-TT-112-03"]}]},{"name":"Mackay Memorial Hospital","award":["MMH-TT-11003"],"award-info":[{"award-number":["MMH-TT-11003"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Diagnostics"],"abstract":"<jats:p>Background: Accurate localization of internal carotid artery (ICA) occlusion is critical for optimizing endovascular thrombectomy (EVT) strategies. Conventional multiphase CT angiography (mCTA) often omits the carotid bifurcation in delayed phases, limiting differentiation between true cervical ICA occlusion and pseudo-occlusion. Methods: We retrospectively analyzed 56 acute ischemic stroke patients with ICA occlusion who underwent EVT and extended-range mCTA between 2016 and 2020. The scan range of the second and third arterial phases was modified to include the carotid bifurcation. Imaging patterns were evaluated to distinguish bifurcation stenosis with superimposed occlusion from proximal ICA occlusion, and to infer thrombus location by comparing arterial opacification levels across phases. Results: Extended mCTA significantly improved visualization of ICA enhancement patterns in delayed phases (p &lt; 0.001). Cases with bifurcation stenosis showed consistently lower and stable opacification levels across phases, whereas proximal ICA occlusion demonstrated progressive contrast advancement. Distal occlusion, particularly beyond the ophthalmic artery, showed higher opacification. Including the carotid bifurcation increased scan length by ~10%, with acceptable radiation exposure. Conclusions: Incorporating the carotid bifurcation into delayed mCTA phases enhances the ability to differentiate occlusion subtypes and estimate thrombus location. This refined imaging approach enables better EVT planning, including device selection and procedural timing, thereby improving patient outcomes in acute stroke care.<\/jats:p>","DOI":"10.3390\/diagnostics15172265","type":"journal-article","created":{"date-parts":[[2025,9,8]],"date-time":"2025-09-08T08:06:32Z","timestamp":1757318792000},"page":"2265","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":1,"title":["Differentiating True Occlusion from Pseudo-Occlusion: The Role of Extended Multiphase Computed Tomography Angiography Scan Range in Internal Carotid Artery Occlusion"],"prefix":"10.3390","volume":"15","author":[{"ORCID":"https:\/\/orcid.org\/0000-0001-5694-8288","authenticated-orcid":false,"given":"Hsin-Fan","family":"Chiang","sequence":"first","affiliation":[{"name":"Department of Radiology, MacKay Memorial Hospital, Taipei 104217, Taiwan"},{"name":"Department of Medicine, MacKay Medical University, New Taipei City 252005, Taiwan"},{"name":"MacKay Junior College of Medicine, Nursing, and Management, Taipei 112021, Taiwan"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-3786-6321","authenticated-orcid":false,"given":"Cheng-Chih","family":"Hsieh","sequence":"additional","affiliation":[{"name":"Department of Radiology, MacKay Memorial Hospital, Taipei 104217, Taiwan"},{"name":"Department of Medicine, MacKay Medical University, New Taipei City 252005, Taiwan"},{"name":"MacKay Junior College of Medicine, Nursing, and Management, Taipei 112021, Taiwan"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0009-0001-2252-6586","authenticated-orcid":false,"given":"Shih-Yang","family":"Wei","sequence":"additional","affiliation":[{"name":"Department of Radiology, MacKay Memorial Hospital, Taipei 104217, Taiwan"},{"name":"Department of Medicine, MacKay Medical University, New Taipei City 252005, Taiwan"},{"name":"MacKay Junior College of Medicine, Nursing, and Management, Taipei 112021, Taiwan"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"An-Bang","family":"Zeng","sequence":"additional","affiliation":[{"name":"Department of Radiology, MacKay Memorial Hospital, Taipei 104217, Taiwan"},{"name":"MacKay Junior College of Medicine, Nursing, and Management, Taipei 112021, Taiwan"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Ching-Chia","family":"Huang","sequence":"additional","affiliation":[{"name":"Department of Radiology, MacKay Memorial Hospital, Taipei 104217, Taiwan"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Cheng-Han","family":"Chan","sequence":"additional","affiliation":[{"name":"Department of Radiology, MacKay Memorial Hospital, Taipei 104217, Taiwan"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Chao-Yang","family":"Zheng","sequence":"additional","affiliation":[{"name":"Department of Radiology, MacKay Memorial Hospital, Taipei 104217, Taiwan"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-0757-6486","authenticated-orcid":false,"given":"Chun-Chao","family":"Huang","sequence":"additional","affiliation":[{"name":"Department of Radiology, MacKay Memorial Hospital, Taipei 104217, Taiwan"},{"name":"Department of Medicine, MacKay Medical University, New Taipei City 252005, Taiwan"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2025,9,7]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"417","DOI":"10.1016\/S1474-4422(19)30030-4","article-title":"The global burden of stroke: Persistent and disabling","volume":"18","author":"Gorelick","year":"2019","journal-title":"Lancet Neurol."},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"11","DOI":"10.1056\/NEJMoa1411587","article-title":"A randomized trial of intraarterial treatment for acute ischemic stroke","volume":"372","author":"Berkhemer","year":"2015","journal-title":"N. Engl. J. Med."},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"1009","DOI":"10.1056\/NEJMoa1414792","article-title":"Endovascular therapy for ischemic stroke with perfusion-imaging selection","volume":"372","author":"Campbell","year":"2015","journal-title":"N. Engl. J. Med."},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"1019","DOI":"10.1056\/NEJMoa1414905","article-title":"Randomized assessment of rapid endovascular treatment of ischemic stroke","volume":"372","author":"Goyal","year":"2015","journal-title":"N. Engl. J. Med."},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"2296","DOI":"10.1056\/NEJMoa1503780","article-title":"Thrombectomy within 8 hours after symptom onset in ischemic stroke","volume":"372","author":"Jovin","year":"2015","journal-title":"N. Engl. J. Med."},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"2285","DOI":"10.1056\/NEJMoa1415061","article-title":"Stent-retriever thrombectomy after intravenous t-pa vs. T-pa alone in stroke","volume":"372","author":"Saver","year":"2015","journal-title":"N. Engl. J. Med."},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"107","DOI":"10.1007\/s10198-018-0984-0","article-title":"Economic burden of stroke: A systematic review on post-stroke care","volume":"20","author":"Rajsic","year":"2019","journal-title":"Eur. J. Health Econ. HEPAC Health Econ. Prev. Care"},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"e344","DOI":"10.1161\/STR.0000000000000211","article-title":"Guidelines for the early management of patients with acute ischemic stroke: 2019 update to the 2018 guidelines for the early management of acute ischemic stroke: A guideline for healthcare professionals from the american heart association\/american stroke association","volume":"50","author":"Powers","year":"2019","journal-title":"Stroke"},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"209","DOI":"10.1159\/000448525","article-title":"Improving the evaluation of collateral circulation by multiphase computed tomography angiography in acute stroke patients treated with endovascular reperfusion therapies","volume":"5","author":"Carvalho","year":"2016","journal-title":"Interv. Neurol."},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"1453","DOI":"10.1161\/STROKEAHA.115.009160","article-title":"Role of imaging in current acute ischemic stroke workflow for endovascular therapy","volume":"46","author":"Menon","year":"2015","journal-title":"Stroke"},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"221","DOI":"10.3174\/ajnr.A6889","article-title":"Multiphase ct angiography: A useful technique in acute stroke imaging\u2014Collaterals and beyond","volume":"42","author":"Dundamadappa","year":"2021","journal-title":"Am. J. Neuroradiol."},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"1008","DOI":"10.1148\/radiol.2017170681","article-title":"Cervical internal carotid occlusion versus pseudo-occlusion at ct angiography in the context of acute stroke: An accuracy, interobserver, and intraobserver agreement study","volume":"286","author":"Diouf","year":"2018","journal-title":"Radiology"},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"774","DOI":"10.1161\/STROKEAHA.116.015427","article-title":"Cervical carotid pseudo-occlusions and false dissections: Intracranial occlusions masquerading as extracranial occlusions","volume":"48","author":"Grossberg","year":"2017","journal-title":"Stroke"},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"983","DOI":"10.1136\/neurintsurg-2017-013708","article-title":"Cervical ica pseudo-occlusion on single phase cta in patients with acute terminal ica occlusion: What is the mechanism and can delayed cta aid diagnosis?","volume":"10","author":"Wareham","year":"2018","journal-title":"J. NeuroInterventional Surg."},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"1265","DOI":"10.1161\/STROKEAHA.120.031797","article-title":"Tandem lesions in anterior circulation stroke: Analysis of the german stroke registry\u2013endovascular treatment","volume":"52","author":"Feil","year":"2021","journal-title":"Stroke"},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"510","DOI":"10.1148\/radiol.15142256","article-title":"Multiphase ct angiography: A new tool for the imaging triage of patients with acute ischemic stroke","volume":"275","author":"Menon","year":"2015","journal-title":"Radiology"},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"72","DOI":"10.4103\/aian.aian_750_23","article-title":"Ct angiographic patterns predict carotid pseudo-occlusion in acute ischemic stroke","volume":"27","author":"Sachithanandan","year":"2024","journal-title":"Ann. Indian Acad. Neurol."},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"825","DOI":"10.1016\/j.otc.2005.03.017","article-title":"Anatomy of the orbit and its related structures","volume":"38","author":"Burkat","year":"2005","journal-title":"Otolaryngol. Clin. N. Am."}],"container-title":["Diagnostics"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/2075-4418\/15\/17\/2265\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,9]],"date-time":"2025-10-09T18:41:35Z","timestamp":1760035295000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/2075-4418\/15\/17\/2265"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2025,9,7]]},"references-count":18,"journal-issue":{"issue":"17","published-online":{"date-parts":[[2025,9]]}},"alternative-id":["diagnostics15172265"],"URL":"https:\/\/doi.org\/10.3390\/diagnostics15172265","relation":{},"ISSN":["2075-4418"],"issn-type":[{"value":"2075-4418","type":"electronic"}],"subject":[],"published":{"date-parts":[[2025,9,7]]}}}