[{"data":1,"prerenderedAt":-1},["ShallowReactive",2],{"doc-detail-85146-en":3,"doc-seo-85146-105":29,"detail-sidebar-cat-0-en-105":91},{"code":4,"msg":5,"data":6},0,"success",{"doc_id":7,"user_id":8,"nickname":9,"user_avatar":10,"doc_module":4,"category_id":11,"category_name":12,"doc_title":13,"doc_description":14,"doc_content":15,"file_id":16,"file_url":17,"file_type":18,"file_size":19,"view_count":20,"is_deleted":4,"is_public":20,"is_downloadable":20,"audit_status":20,"page_count":21,"language":22,"language_code":23,"site_id":24,"html_lang":23,"table_of_contents":25,"faqs":26,"seo_title":13,"seo_description":14,"update_tm":27,"read_time":28},85146,1374391974468,"Eden","https://ap-avatar.wpscdn.com/davatar_29158cc5080c5b710cf443261637dec0",8,"Research & Report","A Unified Model for Highly Accurate ECG-Free Dynamic Coronary Roadmapping Using Spatio Temporal Transformers","Percutaneous Coronary Intervention (PCI) requires repeated iodine contrast injections to visualize coronary arteries, increasing radiation exposure and the risk of contrast-induced nephropathy, including acute kidney injury in patients with renal impairment. Dynamic Coronary Roadmapping (DRM) reduces these risks by overlaying a precomputed angiographic vessel map onto live fluoroscopy and continuously updating it. Accurate DRM depends on cardiac phase matching and reliable catheter tip tracking for motion compensation. The unified framework addresses ECG-free settings via large-scale spatio-temporal pretraining, auxiliary ECG R-peak and tracking tasks, and robust majority-voting postprocessing with confidence linked to phase error, validated on clinical X-ray datasets.","A Unified Model for Highly Accurate ECG-Free Dynamic Coronary Roadmapping Using Spatio-Temporal Transformers⋆  \nSaahil Islama,c,∗,1 , Sebastian Piatb , Venkatesh N. Murthyb , Serkan Cimenb , Puneet Sharmab , Andreas Maiera and Florin C. Ghesuc  \na Pattern Recognition Lab, Friedrich Alexander University, Erlangen, Germany b Digital Technology and Innovation, Siemens Healthineers, Princeton, USAc Digital Technology and Innovation, Siemens Healthineers, Erlangen, Germany  \narXiv :2607 .09805v1 [ ee ss .IV] 9 Jul 2026  \nARTICLE INFO  \nKeywords:  \nDynamic Coronary Roadmapping ECG-free Motion Compensation  \nSelf-supervised spatio-temporal encoder Cardiac Phase Matching  \nUnified Model  \nImage-Guided Intervention  \nAB STRACT  \nPercutaneous Coronary Intervention (PCI) is a minimally invasive procedure designed to restore coronary blood flow obstructed by atherosclerotic plaque. During PCI, repeated injections of iodinebased contrast agents are required to visualize the coronary arteries and guide interventional devices. However, frequent injections increase radiation exposure and the risk of contrast-induced nephropathy, with acute kidney injury reported in up to 30% of patients with renal impairment. Dynamic Coronary Roadmapping (DRM) has emerged as an effective strategy to mitigate these risks by overlaying aprecomputed angiographic vessel map onto live fluoroscopy and continuously updating it during the procedure. Accurate DRM depends on precise cardiac phase matching between angiography and fluoroscopy, as well as reliable catheter tip tracking for motion compensation. These tasks remain challenging in electrocardiogram-free settings or when manual annotations are limited. In this work, we introduce a unified DRM framework that simultaneously performs cardiac phase matching and catheter tip tracking, enabling accurate and real-time guidance. Our approach employs a large-scalespatio-temporal encoder pretrained on 16 million frames to model cardiac motion dynamics. To our knowledge, it is the first time this kind of pretraining has been used for motion compensation in DRM. Furthermore, we propose auxiliary tasks based on ECG R-peak detection and catheter tip tracking, which stabilize optimization and eliminate the need for extensive catheter mask annotations. Finally, a majority-voting postprocessing strategy aggregates temporal predictions to enhance robustness and provides a confidence score that correlates with the phase-matching error. Comprehensive evaluationson clinical X-ray datasets show that the proposed method achieves state-of-the-art performance, producing low temporal misalignment and consistent phase-matching accuracy suitable for real-time DRM applications.  \n1. Introduction  \nPercutaneous Coronary Intervention (PCI) is a minimally invasive cardiology procedure performed to restore blood flow in coronary arteries obstructed by atherosclerotic plaque deposits, a condition commonly referred to as stenosis (Khan and Ludman (2022)) . Under X-ray angiographic guidance, a catheter is navigated into the ostium of the coronary artery. Through this guiding catheter, a balloon catheter equipped with a stent is advanced over a guidewire to the stenotic site. Inflation of the balloon expands the stent, which is subsequently deployed to maintain vessel patency and prevent restenosis. To visualize the coronary vasculature and guide the catheter and guidewire to the stenotic region, an iodine-based contrast agent is injected during the procedure. However, opacification of coronary arteries only lasts fora short period of time and the contrast agent is injected multiple times for navigation of devices. Moreover, cardiologists have to mentally reconstruct the position of vessels and stenosis based on previous angiograms. This practice poses risks such as radiation exposure and contrast-induced  \n⋆  \n∗ Saahil Islam  \n [saahil.islam@fau.de](saahil.islam@fau.de) (S. Islam)  \n (S. Islam) ORCID(s):  \n1  \nnephropathy. In patients with pre-e","cbCailg4528EU9CW","https://ap.wps.com/l/cbCailg4528EU9CW","pdf",5458928,1,13,"English","en",105,"# Introduction\n## Dynamic Coronary Roadmapping","[{\"question\":\"Why are repeated contrast injections used during PCI, and what risks do they create?\",\"answer\":\"PCI uses iodine-based contrast to visualize coronary arteries and guide devices, but the contrast lasts only briefly, so injections are repeated. This increases radiation exposure and the risk of contrast-induced nephropathy, with acute kidney injury reported up to 30% in patients with renal impairment.\"},{\"question\":\"What determines the accuracy of Dynamic Coronary Roadmapping (DRM)?\",\"answer\":\"Accurate DRM requires precise cardiac phase matching between angiography and fluoroscopy, plus reliable catheter tip tracking to compensate for motion. These are especially challenging in ECG-free settings or with limited manual annotations.\"},{\"question\":\"How does the proposed unified model achieve ECG-free, real-time DRM guidance?\",\"answer\":\"The method jointly performs cardiac phase matching and catheter tip tracking using a large-scale spatio-temporal encoder pretrained on 16 million frames. It adds auxiliary tasks for ECG R-peak detection and catheter tracking to stabilize optimization, then uses majority-voting postprocessing to improve robustness and output confidence correlated with phase-matching error.\"}]",1784201370,33,{"code":4,"msg":30,"data":31},"ok",{"site_id":24,"language":23,"slug":32,"title":13,"keywords":33,"description":14,"schema_data":34,"social_meta":86,"head_meta":88,"extra_data":90,"updated_unix":27},"a-unified-model-for-highly-accurate-ecg-free-dynamic-coronary-roadmapping-using-spatio-temporal-transformers","",{"@graph":35,"@context":85},[36,53,68],{"@type":37,"itemListElement":38},"BreadcrumbList",[39,43,47,50],{"item":40,"name":41,"@type":42,"position":20},"https://docshare.wps.com","Home","ListItem",{"item":44,"name":45,"@type":42,"position":46},"https://docshare.wps.com/document/","Document",2,{"item":48,"name":12,"@type":42,"position":49},"https://docshare.wps.com/document/research-report/",3,{"item":51,"name":13,"@type":42,"position":52},"https://docshare.wps.com/document/a-unified-model-for-highly-accurate-ecg-free-dynamic-coronary-roadmapping-using-spatio-temporal-transformers/85146/",4,{"url":51,"name":13,"@type":54,"author":55,"headline":13,"publisher":57,"fileFormat":60,"inLanguage":23,"description":14,"dateModified":61,"datePublished":62,"encodingFormat":60,"isAccessibleForFree":63,"interactionStatistic":64},"DigitalDocument",{"name":9,"@type":56},"Person",{"url":40,"name":58,"@type":59},"DocShare","Organization","application/pdf","2026-07-23","2026-07-16",true,{"@type":65,"interactionType":66,"userInteractionCount":20},"InteractionCounter",{"@type":67},"ViewAction",{"@type":69,"mainEntity":70},"FAQPage",[71,77,81],{"name":72,"@type":73,"acceptedAnswer":74},"Why are repeated contrast injections used during PCI, and what risks do they create?","Question",{"text":75,"@type":76},"PCI uses iodine-based contrast to visualize coronary arteries and guide devices, but the contrast lasts only briefly, so injections are repeated. This increases radiation exposure and the risk of contrast-induced nephropathy, with acute kidney injury reported up to 30% in patients with renal impairment.","Answer",{"name":78,"@type":73,"acceptedAnswer":79},"What determines the accuracy of Dynamic Coronary Roadmapping (DRM)?",{"text":80,"@type":76},"Accurate DRM requires precise cardiac phase matching between angiography and fluoroscopy, plus reliable catheter tip tracking to compensate for motion. These are especially challenging in ECG-free settings or with limited manual annotations.",{"name":82,"@type":73,"acceptedAnswer":83},"How does the proposed unified model achieve ECG-free, real-time DRM guidance?",{"text":84,"@type":76},"The method jointly performs cardiac phase matching and catheter tip tracking using a large-scale spatio-temporal encoder pretrained on 16 million frames. 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