Accuracy of real-time imaging fusion between echocardiography and fluoroscopy in the catheterization laboratory of congenital heart diseases

Abstract

The Echonavigator ® software allows real-time imaging fusion between 2D or 3D echocardiography and fluoroscopy in the catheterization laboratory. We aim to test the accuracy of the imaging fusion in a pediatric population. After percutaneous closure of atrial septal defect, occluder devices, visualized on echocardiography and fluoroscopy, were used as a reference tool. First, distance between the thread pitch on the 3D echo view and on fluoroscopy was measured on 4 orthogonal views (right anterior oblique, left anterior oblique, right posterior oblique, left posterior oblique), in systole and diastole (distance 1). Second, distance between a marker positionned on echo and the thread pitch on the fluoroscopy view was measured on the 4 orthogonal views in systole and diastole (distance 2). Thirty-one patients (7.9 years old [6.0–9.8]; 26 Kg [21–37]) were included. Fusion and marker positioning were feasible in all cases. No complication related to the echocardiography was reported. In 5 cases (16.1%), fusion was instable during the procedure with transient loss of the automatic tracking of the probe. Quality of the fusion imaging was rated good in 21 cases (67.7%) and excellent in 10 cases (32.3%). Fusion was available in real time in all patients. However there was a slight temporal delay between the fluoroscopic and the echo images. Minimal and maximal distances 1 were 0.5 [0–0.5] and 2 mm [1.5–2.5]. The marker positionned on echo was fixed and did not follow the movement of the thread pitch during the cardiac cycle. On the fusion view, minimal and maximal distances 2 during the cardiac cycle were 0.5 [0.3–1] and 2 mm [1.5–2.5]. Bias was not significantly different among the 4 axis ( Fig. 1 ). Feasibility and accuracy of the echonavigator software is high in a pediatric population weighting more than 20 Kg. It could be improved by the development of a pediatric 3D trans-esophageal probe and by applying 3D speckle tracking technology.