Showing papers by "Gemma Piella published in 2012"

SPM to the heart: Mapping of 4D continuous velocities for motion abnormality quantification

Abstract: This paper proposes to apply parallel transport and statistical atlas techniques to quantify 4D myocardial motion abnormalities. We take advantage of our previous work on cardiac motion, which provided a continuous spatiotemporal representation of velocities, to interpolate and reorient cardiac motion fields to an unbiased reference space. Abnormal motion is quantified using SPM analysis on the velocity fields, which includes a correction based on random field theory to compensate for the spatial smoothness of the velocity fields. This paper first introduces the imaging pipeline for constructing a continuous 4D velocity atlas. This atlas is then applied to quantify abnormal motion patterns in heart failure patients.

Temporal diffeomorphic free form deformation to quantify changes induced by left and right bundle branch block and pacing

Abstract: This paper presents motion and deformation quantification results obtained from synthetic and in vitro phantom data provided by the second cardiac Motion Analysis Challenge at STACOM-MICCAI We applied the Temporal Diffeomorphic Free Form Deformation (TDFFD) algorithm to the datasets This algorithm builds upon a diffeomorphic version of the FFD, to provide a 3D+t continuous and differentiable transform The similarity metric includes a comparison between consecutive images, and between a reference and each of the following images Motion and strain accuracy were evaluated on synthetic 3D ultrasound sequences with known ground truth motion Experiments were also conducted on in vitro acquisitions

Atlas-based quantification of myocardial motion abnormalities: added-value for understanding the effect of cardiac resynchronization therapy.

Abstract: Statistical atlases may help improving the analysis of cardiac wall-motion abnormalities. This study aims at demonstrating the clinical value of such a method to better understand the effect of cardiac resynchronization therapy (CRT). We compared an atlas of normal septal motion built using apical four-chamber two-dimensional echocardiographic sequences from healthy volunteers with 88 patients undergoing CRT at baseline and at 12 months follow-up. Abnormal motion was quantified locally using a p value based on a statistical distance to normality. Reduction ≥15% in left ventricle end-systolic volume defined CRT response. Responders showed significantly higher reduction of abnormalities (p ≤ 0.001). Non-responders conserved abnormal septal motion at the end of the isovolumic contraction (IVC). A specific inward-outward motion of the septum during IVC predominated in responders and was corrected at follow-up. The method is of interest to characterize patterns of mechanical dyssynchrony and to study the link between their evolution and CRT response.

Endocardial motion estimation from electro-anatomical data

Abstract: An accurate scar characterization plays an essential role for the treatment of ventricular tachycardia in patients with ischemic cardiomyopathy. Cardiac ablation based on electrical information is a widely used procedure to fix ventricular tachycardia. However, intra-operative scar characterization may be improved using mechanical information together with the electrical data. We propose in this paper a method to reconstruct the endocardial motion intra-operatively by exploiting both information from an electro-anatomical mapping system and the heart anatomy segmented from any pre-operative 3D imaging modality, using a bilinear statistical atlas to approximate motion in the areas where no information is provided. We applied the proposed methodology to four patients with ischemic cardiomyopathy. The results showed abnormal strain curves in presence of scar, which was defined using contrast-enhanced magnetic resonance images.