Standardized unfold mapping: a technique to permit left atrial regional data display and analysis

Williams, Steven E.; Tobón Gómez, Catalina, 1981-; Zuluaga, Maria A.; Chubb, Henry; Butakoff, Constantine; Karim, Rashed; Ahmed, Elena; Camara, Oscar; Rhode, Kawal

doi:http://dx.doi.org/10.1007/s10840-017-0281-3

Standardized unfold mapping: a technique to permit left atrial regional data display and analysis

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Williams SE, Tobon-Gomez C, Zuluaga MA, Chubb H, Butakoff C, Karim R, Ahmed E, Camara O, Rhode KS. Standardized unfold mapping: a technique to permit left atrial regional data display and analysis. Card Electrophysiol Rev. 2017;50:125-31. DOI: 10.1007/s10840-017-0281-3

Abstract

Purpose: Left atrial arrhythmia substrate assessment can involve multiple imaging and electrical modalities, but visual analysis of data on 3D surfaces is time-consuming and suffers from limited reproducibility. Unfold maps (e.g., the left ventricular bull’s eye plot) allow 2D visualization, facilitate multimodal data representation, and provide a common reference space for inter-subject comparison. The aim of this work is to develop a method for automatic representation of multimodal information on a left atrial standardized unfold map (LA-SUM). Methods: The LA-SUM technique was developed and validated using 18 electroanatomic mapping (EAM) LA geometries before being applied to ten cardiac magnetic resonance/EAM paired geometries. The LA-SUM was defined as an unfold template of an average LA mesh, and registration of clinical data to this mesh facilitated creation of new LA-SUMs by surface parameterization. Results: The LA-SUM represents 24 LA regions on a flattened surface. Intra-observer variability of LA-SUMs for both EAM and CMR datasets was minimal; root-mean square difference of 0.008 ± 0.010 and 0.007 ± 0.005 ms (local activation time maps), 0.068 ± 0.063 gs (force-time integral maps), and 0.031 ± 0.026 (CMR LGE signal intensity maps). Following validation, LA-SUMs were used for automatic quantification of post-ablation scar formation using CMR imaging, demonstrating a weak but significant relationship between ablation force-time integral and scar coverage (R 2 = 0.18, P < 0.0001). Conclusions: The proposed LA-SUM displays an integrated unfold map for multimodal information. The method is applicable to any LA surface, including those derived from imaging and EAM systems. The LA-SUM would facilitate standardization of future research studies involving segmental analysis of the LA.