Non-rigid Registration of Vascular Structures for Aligning 2D X-ray Angiography with 3D CT Angiography

Abstract

Abstract. The alignment of pre-operative 3D scans with intra-operative 2D images is important for providing better image guidance. Specifically, overlaying the 3D centerlines of coronary arteries on top of X-ray angiography images reduces the uncertainty inherent in 2D images used during cardiovascular interventions. Because of the dynamic cardiovascular motion from the heartbeat and respiration, a non-rigid registration approach should be applied in contrast registration of the static vascular structure. In this paper, a modified TPS-RPM method is adopted as a non-rigid registration based on a feature-based approach. The proposed method is evaluated on 12 clinical datasets to highlight the necessity of a non-rigid registration approach. IntroductionImage registration between pre-operative images and intra-operative images is a vital technology for image-guided surgery. X-ray angiography (XA) is the modality most commonly used during percutaneous coronary intervention (PCI) for visualization of vessel anatomy and catheter guidance because it is able to capture temporal changes in vessel structures during intervention. However, vessel structures are visible only for 20 seconds after a contrast medium is injected, and the projective nature of angiography makes it difficult for the physician to guide the catheter through the patient's vessel system. Similar challenges occur for other minimally invasive procedures [1,2]. To overcome these challenges, a pre-operative image modality is acquired to yield a 3D total anatomic view that can be used to reduce visual uncertainty and to assess the region of occlusion when planning the intervention. Currently, the most commonly used pre-operative imaging modality for percutaneous coronary interventions is 3D computed tomography angiography (CTA) as a complement. Therefore, image registration between CTA and XA provides surgeons with 3D depth perception and better guidance of the catheter, which leads to increased accuracy.

Rapid and Accurate Registration Method between Intraoperative 2D XA and Preoperative 3D CTA Images for Guidance of Percutaneous Coronary Intervention

“…For the accuracy evaluation, the ADD between the registration result and the ground truth is measured for the centerline, marker, and bifurcation points. The centerline accuracy results for the proposed method, Kim et al [15], and Park et al [17] are 1.2520 mm, 1.2237 mm, and 1.4098 mm, respectively. These values are observed to be numerically similar.…”

“…In this study, we compare the registration accuracy and speed of our method with those of the methods suggested by Kim et al [15] and Park et al [17]. Experiments are performed on the same environment and data.…”

“…These values are observed to be numerically similar. However, as shown in Figure 9(a), the bifurcation points do not align in Kim et al [15], where some vessels converge to a local minimum in a nonrigid registration process [15]. Additionally, the registration method proposed by Park et al [17] shows the incorrect registration result due to the local error in the initial and correction registration process using the principal axis as shown in Figure 9(b).…”

“…However, it required extensive processing time for 3D space registration and could not be applied to the general, single XA image. Kim et al extracted vascular centerlines from XA and CTA images and projected 3D vessels onto 2D vessels for registration [14, 15]. In this method, the distances between the projected 3D vessels and 2D vessels were minimized by iteratively performing rotation, translation, and scaling transformations.…”

“…The proposed method minimizes unnecessary operations and enables fast and accurate registration by optimizing the performance of each step. We use 20 clinical datasets to evaluate the performance of our method in comparison to the registration accuracy, speed, and robustness achieved by Kim et al [15] and Park et al [17].…”