High Intensity Focused Ultrasound Therapy Guidance System by Image-based Registration for Patients with Cardiac Fibrillation

Abstract

Transesophageal high-intensity focused ultrasound (HIFU) energy can be used to treat cardiac arrhythmia efficiently non-invasively. Since the esophagus is located just behind the heart, it offers a perfect acoustic window. Hence, HIFU can be directed toward the heart to perform ablation. In a previous study a HIFU probe with one 2D US image perpendicular to the esophagus axis for guidance purpose has been proposed. A new dual-mode HIFU probe with two perpendicular 2D US imaging plane is now under development. In this paper we propose a therapy guidance system, based on an intensity-based registration of the two perpendicular 2D US to preoperative 3D CT. As a proof of concept we developed the following evaluation framework on a numerical phantom: 1) we define a ground truth (GT) initial pose inside a CT volume and simulated two perpendicular US images from the CT data; 2) we run the registration framework from 55 randomly defined pose initializations around the initial GT pose; and 3) we estimated the accuracy of the registration by (a) the transformation parameter estimation errors and (b) Target Registration Error (TRE).

Deformable US/CT Image Registration with a Convolutional Neural Network for Cardiac Arrhythmia Therapy

“…In order to produce enough data for the training and testing of our framework and also to look about the robustness of the method, we arbitrary produced 250 poses in a range of ±5 mm on translation and ±5 • in rotation around an initial pose, and we extract all the 2D CT slices using the framework described in [15]. Then we simulated the corresponding US images with the method described in [16].…”