Session S21.2

Multimodality Comparison of Quantitative Volumetric Analysis of the Right Ventricle

L Sugeng, HJ Nesser, L Weinert, J Niel, C Ebner,
R Steringer-Mascherbauer, R Bartolles, R Baumanm,
G Schummers, RM Lang, V Mor-Avi*

University of Chicago
Chicago, IL, USA

Aim: Assessment of the right ventricle by two-dimensional echocardiography (2DE) remains challenging due to its unique geometry and limitations of the current analysis techniques. Today, real-time three-dimensional echocardiography (RT3DE), cardiac magnetic resonance (CMR) and cardiac computed tomography (CCT) can quantify right ventricular (RV) volumes, promising to overcome the limitations of 2DE. Our aim was to test a recently developed technique for volumetric analysis of the right ventricle designed for RT3DE, CMR and CCT on images obtained in RV-shaped phantoms and in patients with a wide range of RV geometry.
Methods: Images were analyzed using prototype software (RV Analysis, TomTec), which uses a combination of views that allow the visualization of the tricuspid valve, RV outflow tract and apex in order to reconstruct RV endocardial surface and directly calculate RV volumes. Volumes measured in-vitro were compared to the true volumes. The human protocol included 25 patients who underwent RT3DE (Philips iE33), CMR (Siemens Sonata) and CT (Toshiba 16-slice scanner) on the same day. Volumetric analysis of CMR images was used as a reference, against which RT3DE and CCT measurements were compared using linear regression and Bland-Altman analyses. To determine the reproducibility of the volumetric analysis, repeated measurements were performed for all three imaging modalities in 11 patients.
Results: The in-vitro measurements showed that: (1) volumetric analysis of CMR images yielded the most accurate measurements; (2) CCT measurements showed slight (4%) but consistent overestimation; (3) RT3DE measurements showed small underestimation, but considerably wider margins of error. Both RT3DE and CCT measurements correlated highly with the CMR reference (r-values 0.86-0.93) and showed the same trends of under- and overestimation noted in-vitro. All inter- and intra-observer variability values were <15%, with those of CMR being the highest.
Conclusions: We tested the recently developed technique of volumetric quantification of RV volume on CMR, CCT and RT3DE images. Eliminating analysis-related inter-modality differences allowed fare comparisons and highlighted the unique limitations of each modality. Understanding these differences promises to aid in the functional assessment of the right ventricle.

(Abstract Control Number: 207)