Ultrasound Navigation for Transcatheter Aortic Stent Deployment Using Global and Local Information

Fang Chen,Hongen Liao,Jia Liu

doi:10.3390/app6120391

Abstract

An ultrasound (US) navigation system using global and local information is presented for transcatheter aortic stent deployment. The system avoids the use of contrast agents and radiation required in traditional fluoroscopically-guided procedures and helps surgeons precisely visualize the surgical site. To obtain a global 3D (three-dimensional) navigation map, we use magnetic resonance (MR) to provide a 3D context to enhance 2D (two-dimensional) US images through image registration. The US images are further processed to obtain the trajectory of interventional catheter. A high-resolution aortic model is constructed by using trajectory and segmented intravascular ultrasound (IVUS) images. The constructed model reflects morphological characteristics of the aorta to provide local navigation information. Our navigation system was validated using in vitro phantom of heart and aorta. The mean target registration error is 2.70 mm and the average tracking error of the multi-feature particle filter is 0.87 mm. These results confirm that key parts of our navigation system are effective. In the catheter intervention experiment, the vessel reconstruction error of local navigation is reduced by 80% compared to global navigation. Moreover, the targeting error of the navigation combining global and local information is reduced compared to global navigation alone (1.72 mm versus 2.87 mm). Thus, the US navigation system which integrates the large view of global navigation and high accuracy of local navigation can facilitate transcatheter stent deployment.

Highlights

Placement of endovascular stent has become a preferred option for treatment of acute aorta dissection and aortosclerosis, because it can reduce the risk of infection and patient trauma [1]
There are two critical factors which directly influence the accuracy of stent deployment: (1) information on morphological characteristics of the aorta, especially calcification or lesion areas, which can greatly assist surgeons to determine the size of stent [2]; (2) intuitive three-dimensional (3D) navigation images which can reflect intraoperative information of cardiac structure [3]
To achieve more stable tracking of aortic cross-section in US images, we propose a multi-feature particle ate initial target position

Summary

Introduction

Placement of endovascular stent has become a preferred option for treatment of acute aorta dissection and aortosclerosis, because it can reduce the risk of infection and patient trauma [1]. Stent placement can replace conventional medical treatment for the majority of patients. Surgeons insert a catheter into aortic lesions to finish the placement of stent. There are two critical factors which directly influence the accuracy of stent deployment: (1) information on morphological characteristics of the aorta, especially calcification or lesion areas, which can greatly assist surgeons to determine the size of stent [2]; (2) intuitive three-dimensional (3D) navigation images which can reflect intraoperative information of cardiac structure [3]. Conventional stent placement, which is typically performed under X-ray, remains challenging, due to several shortcomings of fluoroscopic guidance.

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Conclusion