Niels Nijhof

Evaluation of a real-time hybrid three-dimensional echo and x-ray imaging system for guidance of cardiac catheterisation procedures

Minimally invasive cardiac surgery is made possible by image guidance technology. X-ray fluoroscopy provides high contrast images of catheters and devices, whereas 3D ultrasound is better for visualising cardiac anatomy. We present a system in which the two modalities are combined, with a trans-esophageal echo volume registered to and overlaid on an X-ray projection image in real-time. We evaluate the accuracy of the system in terms of both temporal synchronisation errors and overlay registration errors. The temporal synchronisation error was found to be 10% of the typical cardiac cycle length. In 11 clinical data sets, we found an average alignment error of 2.9 mm. We conclude that the accuracy result is very encouraging and sufficient for guiding many types of cardiac interventions. The combined information is clinically useful for placing the echo image in a familiar coordinate system and for more easily identifying catheters in the echo volume.

First experience with rotational angiography of the right ventricle to guide ventricular tachycardia ablation

BACKGROUND Rotational angiography with three-dimensional reconstruction (3DRA) is a new imaging tool recently introduced to guide mapping and ablation of the left atrium. OBJECTIVE The purpose of this study was to determine the utility of 3DRA for imaging the ventricles and guiding ventricular tachycardia (VT) ablation. METHODS Using the Philips Allura Xper FD10 system, 3DRA was performed in eight patients referred for right ventricular outflow tract (RVOT) VT ablation. The imaging protocol for right ventricular (RV) injection is described. IV contrast was injected at the RA/IVC junction over 4 sec and 3DRA was obtained immediately. Images were segmented manually on the EP Navigator workstation and registered on live fluoroscopy. Intracardiac electrograms were superimposed on 3DRA creating a true electroanatomic map (ElectroNav). CARTO mapping and echocardiograms were performed on all patients, cardiac computed tomography (CT) in 4, and magnetic resonance imaging (MRI) in 1. RESULTS Three-dimensional rotational angiography was successful in 7 of 8 patients. Image interpretation was unsuccessful in one patient due to poor isocentering. RV imaging was performed with 82 ± 18 mL of contrast. RV image segmentation required 19 ± 5 minutes. CARTO maps of the RVOT required 43 ± 12 minutes and additional fluoroscopy. Three-dimensional rotational angiography was used to guide VT ablation by providing realistic anatomic images of the pulmonary valve plane, endo-views of the ventricle, and ablation point tagging. Anatomic detail provided by 3DRA was qualitatively superior to CARTO. VT ablation was acutely successful in all patients. Close concordance between echocardiographic, CT/MRI, and 3DRA measurements of the RVOT was observed (r = 0.9, P <.01). CONCLUSION Three-dimensional rotational angiography of the RV and RVOT is a feasible imaging technique that utilizes a protocol of timed angiography, manual segmentation, image registration, and superimposition of intracardiac electrograms to create an angiogram-based electroanatomic model of these structures.

Novel System for Real-Time Integration of 3-D Echocardiography and Fluoroscopy for Image-Guided Cardiac Interventions: Preclinical Validation and Clinical Feasibility Evaluation

Real-time imaging is required to guide minimally invasive catheter-based cardiac interventions. While transesophageal echocardiography allows for high-quality visualization of cardiac anatomy, X-ray fluoroscopy provides excellent visualization of devices. We have developed a novel image fusion system that allows real-time integration of 3-D echocardiography and the X-ray fluoroscopy. The system was validated in the following two stages: 1) preclinical to determine function and validate accuracy; and 2) in the clinical setting to assess clinical workflow feasibility and determine overall system accuracy. In the preclinical phase, the system was assessed using both phantom and porcine experimental studies. Median 2-D projection errors of 4.5 and 3.3 mm were found for the phantom and porcine studies, respectively. The clinical phase focused on extending the use of the system to interventions in patients undergoing either atrial fibrillation catheter ablation (CA) or transcatheter aortic valve implantation (TAVI). Eleven patients were studied with nine in the CA group and two in the TAVI group. Successful real-time view synchronization was achieved in all cases with a calculated median distance error of 2.2 mm in the CA group and 3.4 mm in the TAVI group. A standard clinical workflow was established using the image fusion system. These pilot data confirm the technical feasibility of accurate real-time echo-fluoroscopic image overlay in clinical practice, which may be a useful adjunct for real-time guidance during interventional cardiac procedures.

Integrated 3D Echo-X Ray to Optimize Image Guidance for Structural Heart Intervention

Real-time, 3-dimensional transesophageal echocardiography (RT 3D TEE) is now used routinely in conjunction with x-ray fluoroscopy to guide percutaneous structural heart disease (SHD) interventions. Unlike fluoroscopy, RT 3D TEE provides excellent detail of 3D anatomy and soft tissue structures, and

Integrated 3D Echo-X-Ray Navigation to Predict Optimal Angiographic Deployment Projections for TAVR

Transcatheter aortic valve replacement (TAVR) is an established and accepted therapeutic option for both inoperable and high-risk surgical patients with severe aortic stenosis. Precise prosthetic valve positioning in the 3-dimensional (3D) aortic annulus is a critical component of a successful TAVR

Fusion Imaging During the Interventional Closure of Patent Foramen Ovale and Atrial Septal Defects: Mandatory or Superfluous?

Real-time fusion imaging has emerged as a sophisticated tool to guide structural heart disease (SHD) interventions. The overlay of 2 different imaging modalities allows the interventionalist to visualize echocardiographic images within a fluoroscopic image that offers intuitive perception of the

Automated anatomical intelligence: next-generation fusion imaging during structural heart interventions

Heart teams performing structural heart interventions face particular imaging difficulties, including separate image orientation and different tissue imaging abilities of the involved techniques. Specialized software (EchoNavigator, Philips Healthcare, Best, The Netherlands) enables fusion of three-dimensional transoesophageal echocardiography and fluoroscopy to overcome such shortcomings. However, visualization of complex anatomical structures and interventional precision within the beating …