Simulated evaluation of an intraoperative surface modeling method for catheter ablation by a real phantom simulation experiment

Abstract

In this work, we propose a phantom experiment method to quantitatively evaluate an intraoperative left-atrial modeling update method. In prior work, we proposed an update procedure which updates the preoperative surface model with information from real-time tracked 2D ultrasound. Prior studies did not evaluate the reconstruction using an anthropomorphic phantom. In this approach, a silicone heart phantom (based on a high resolution human atrial surface model reconstructed from CT images) was made as simulated atriums. A surface model of the left atrium of the phantom was deformed by a morphological operation – simulating the shape difference caused by organ deformation between pre-operative scanning and intra-operative guidance. During the simulated procedure, a tracked ultrasound catheter was inserted into right atrial phantom – scanning the left atrial phantom in a manner mimicking the cardiac ablation procedure. By merging the preoperative model and the intraoperative ultrasound images, an intraoperative left atrial model was reconstructed. According to results, the reconstruction error of the modeling method is smaller than the initial geometric difference caused by organ deformation. As the area of the left atrial phantom scanned by ultrasound increases, the reconstruction error of the intraoperative surface model decreases. The study validated the efficacy of the modeling method.

Development of a patient‐specific atrial phantom model for planning and training of inter‐atrial interventions

“…The first stage is applied to obtain an accurate representation of the patient anatomical details with a particular interest in the design of the atrial boundaries at the inter‐atrial septum region. Previous works have used a similar approach to generate the phantom model for catheter ablation simulation . Nevertheless, they failed to correctly generate the entire inter‐septal wall .…”

“…19,20,28 Nevertheless, they failed to correctly generate the entire interseptal wall. 19,20 Secondly (i.e., stage 2), the atrial and wall surfaces are exported into a CAD tool, virtually generating a mold that represents the target anatomy. Due to software (CAD) limitations with extreme irregular shapes, smoothed atrial surfaces were used (obtained through MITK), decimating the detailed mesh and making it suitable for the CAD software.…”

“…Previous works have used a similar approach to generate the phantom model for catheter ablation simulation . Nevertheless, they failed to correctly generate the entire inter‐septal wall . Secondly (i.e., stage 2), the atrial and wall surfaces are exported into a CAD tool, virtually generating a mold that represents the target anatomy.…”

“…Recently, some authors focused on atrial phantom models. 11,18,19 These models were mainly used for training/planning of cardiac ablations, 19,20 presenting the atrial body and the proximal part of the pulmonary veins. Nevertheless, these solutions were either rigid 19 or not appropriate for ultrasound (US) acquisition.…”

“…Nevertheless, these solutions were either rigid or not appropriate for ultrasound (US) acquisition . Furthermore, the thin and complex inter‐atrial wall was not correctly modeled, hampering the identification of the atrial anatomy. Finally, the accuracy of the manufacturing technique was rarely assessed (i.e., the error between the virtually designed model and the physical one).…”