Time-resolved three-dimensional imaging of the left atrium and pulmonary veins in the interventional suite - A comparison between muttisweep gated rotational three-dimensional reconstructed fluoroscopy and multislice computed tomography
ABSTRACT Cardiac computed tomography (CT) is commonly used to visualize left atrial (LA) anatomy for ablation of atrial fibrillation. We have developed a new imaging technique that allows acquisition and visualization of three-dimensional (3D) cardiac images in the catheter lab.
We sought to compare LA and pulmonary vein (PV) dimensions acquired using gated multisweep rotational fluoroscopy (C-arm CT) system and multislice computed tomography (MSCT) in an in vivo porcine model.
A Siemens AXIOM Artis dTA C-arm system (Siemens AG, Medical Solutions) was modified to allow acquisition of four bidirectional sweeps during synchronized acquisition of the electrocardiogram signal to allow retrospective gating. C-arm CT image volumes were then reconstructed. Gated MSCT (SOMATOM Sensation 16 and 64, Siemens AG, Medical Solutions) and C-arm CT images were acquired in six animals. The two main PV diameters were measured in orthogonal axes. LA volumes were calculated. C-arm CT measurements were compared with the MSCT measurements.
The average PV diameters using the C-arm CT were 2.24 x 1.35 cm, versus 2.27 x 1.38 cm for CT. The average difference was 0.034 cm (1.9%) between the C-arm CT and standard CT. The average LA volume using MSCT was 49.1 +/- 12.7 cm(3), as compared with 51.0 +/- 8.7 cm(3) obtained by the C-arm CT. The average difference between the C-arm CT and the MSCT was 1.9 cm(3) (3.7%). There were no significant differences in either the PV or LA measurements.
Visualization of 3D cardiac anatomy during ablation procedures is possible and highly accurate. The 3D cardiac reconstructions acquired during ablation procedures will be valuable for procedural planning and guidance.
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ABSTRACT: With increasing complexity in electrophysiology (EP) procedures, the use of electroanatomic mapping systems (EAMS) as a supplement to fluoroscopy has become common practice. This is the first study that evaluates spatial and point localization accuracy for 2 current EAMS, CARTO3® (Biosense Webster, Diamond Bar, CA, USA) and EnSite Velocity® (St. Jude Medical Inc., St. Paul, MN, USA), and for a novel overlay guidance (OG) software (Siemens AG, Forchheim, Germany) in a phantom experiment. A C-arm CT scan was performed on an acrylic phantom containing holes and location markers. Spatial accuracy was assessed for each system using distance measurements involving known markers inside the phantom and properly placed catheters. Anatomical maps of the phantom were acquired by each EAMS, whereas the 3D-based OG software superimposed an overlay image of the phantom, segmented from the C-arm CT data set, onto biplane fluoroscopy. Registration processes and landmark measurements quantitatively assessed the spatial accuracy of each technology with respect to the ground truth phantom. Point localization performance was 0.49 ± 0.25 mm in OG, 0.46 ± 0.17 mm in CARTO3® and 0.79 ± 0.83 mm in EnSite®. The registration offset between virtual visualization and reality was 1.10 ± 0.52 mm in OG, 1.62 ± 0.77 mm in CARTO3® and 2.02 ± 1.21 mm in EnSite®. The offset to phantom C-arm CT landmark measurements was 0.30 ± 0.26 mm in OG, 0.24 ± 0.21 mm in CARTO3® and 1.32 ± 0.98 mm in EnSite®. Each of the evaluated EP guidance systems showed a high level of accuracy; the observed offsets between the virtual 3D visualization and the real phantom were below a clinically relevant threshold of 3 mm.Journal of Cardiovascular Electrophysiology 08/2013; 25(1). DOI:10.1111/jce.12264 · 3.48 Impact Factor
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ABSTRACT: Purpose: X-ray fluoroscopically guided cardiac electrophysiology (EP) procedures are commonly carried out to treat patients with arrhythmias. X-ray images have poor soft tissue contrast and, for this reason, overlay of a three-dimensional (3D) roadmap derived from preprocedural volumetric images can be used to add anatomical information. It is useful to know the position of the catheter electrodes relative to the cardiac anatomy, for example, to record ablation therapy locations during atrial fibrillation therapy. Also, the electrode positions of the coronary sinus (CS) catheter or lasso catheter can be used for road map motion correction.Methods: In this paper, the authors present a novel unified computational framework for image-based catheter detection and tracking without any user interaction. The proposed framework includes fast blob detection, shape-constrained searching and model-based detection. In addition, catheter tracking methods were designed based on the customized catheter models input from the detection method. Three real-time detection and tracking methods are derived from the computational framework to detect or track the three most common types of catheters in EP procedures: the ablation catheter, the CS catheter, and the lasso catheter. Since the proposed methods use the same blob detection method to extract key information from x-ray images, the ablation, CS, and lasso catheters can be detected and tracked simultaneously in real-time.Results: The catheter detection methods were tested on 105 different clinical fluoroscopy sequences taken from 31 clinical procedures. Two-dimensional (2D) detection errors of 0.50 ± 0.29, 0.92 ± 0.61, and 0.63 ± 0.45 mm as well as success rates of 99.4%, 97.2%, and 88.9% were achieved for the CS catheter, ablation catheter, and lasso catheter, respectively. With the tracking method, accuracies were increased to 0.45 ± 0.28, 0.64 ± 0.37, and 0.53 ± 0.38 mm and success rates increased to 100%, 99.2%, and 96.5% for the CS, ablation, and lasso catheters, respectively. Subjective clinical evaluation by three experienced electrophysiologists showed that the detection and tracking results were clinically acceptable.Conclusions: The proposed detection and tracking methods are automatic and can detect and track CS, ablation, and lasso catheters simultaneously and in real-time. The accuracy of the proposed methods is sub-mm and the methods are robust toward low-dose x-ray fluoroscopic images, which are mainly used during EP procedures to maintain low radiation dose.Medical Physics 07/2013; 40(7):071902. DOI:10.1118/1.4808114 · 3.01 Impact Factor
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ABSTRACT: While the Medtronic O-arm was developed for image-guidance applications during orthopedic procedures, it has potential to assist in cardiac surgical and electrophysiological applications; the purpose of this study was to evaluate the feasibility of using a mobile conebeam imaging system (O-arm) for gated cardiac imaging. In an in vivo study (two pigs), projection data from four independently acquired breath-held scans were combined to obtain cardiac gated 3D images. Projection images were acquired during the infusion of contrast agent and while tracking the ECG. Both standard and high-definition modes of the O-arm were evaluated. Projection data were retrospectively combined to generate images corresponding to systole and diastole; different acceptance windows were investigated. The contrast to noise ratio (CNR) between blood and myocardium was compared for the different gating strategies. Gated cardiac images were successfully reconstructed with as few as two scans combined (CNR = 2.5) and a window of 200 ms. Improved image quality was achieved when selecting views based on the minimum time from the selected phase point in the cardiac cycle, rather than a fixed window; in this case the effective temporal window increased to 475 ms for two scans. The O-arm has the potential to be used as a mobile cardiac imaging system, capable of three-dimensional imaging.Proceedings of SPIE - The International Society for Optical Engineering 02/2012; DOI:10.1117/12.912886 · 0.20 Impact Factor