A novel three-dimensional navigation technology for ultrasound-guided transcarotid artery revascularization

<h2>ABSTRACT</h2><h3>Objective</h3> TransCarotid artery Revascularization is a rapidly growing therapy for carotid stenosis. Compared to carotid endarterectomy, TransCarotid artery Revascularization involves significant radiation exposure to both patient and surgeons. In this study, an innovative fluoroscopy-sparing technique was evaluated to guide stent placement precisely in the carotid artery using real-time navigated ultrasound fused with preoperative CT imaging. <h3>Methods</h3> The endovascular navigation approach combined a clinical ultrasound unit and optical tracking system to visualize and localize 2D ultrasound images in 3D space. Testing with an ultrasound imaging phantom in an operating room environment to evaluate feasibility and accuracy of the method was performed. Preoperative CT scans of the phantom were acquired along with tracked, in-procedure ultrasound sweeps to create 3D artery models from each of the two image volumes. The CT and ultrasound models were aligned automatically through multi-step registration that enabled real-time visualization of the ultrasound image feed overlaid on the 3D CT artery model. In-procedure stents and guidewires were identified on 2D ultrasound, and their 3D locations were overlaid on the 3D artery model along with the ultrasound image. This real-time, navigation interface guided surgeon placement of a 40 mm stent across an artificial 20 mm lesion in the carotid artery phantom. After stent placement, a postoperative CT was acquired to quantify accuracy of stent positioning, measured as distance from stent center point to lesion center point. Technical success was assessed in terms of lesion coverage by the stent placed using the coregistered (to pre-procedure CT) ultrasound image guidance. <h3>Results</h3> Six procedures were performed with 100% technical success rate. Average stent positioning accuracy was 1.3±1.1 mm. Registration accuracy between CT and ultrasound model alignment was 1.0±0.4 mm on average. Total time for image registration, including image acquisition and processing, was 91±6 seconds on average. <h3>Conclusions</h3> A fluoroscopy-sparing ultrasound-based endovascular navigation approach is both accurate and efficient for endovascular stent placement. The method provided intuitive, real-time 3D navigation of instruments relative to arterial anatomy and did not rely on expertise with ultrasound imaging. The technique leveraged existing technologies and workflows while obviating the need for fluoroscopy and shows promise for being evaluated in clinical studies in the future.