- Technologist presentation
- Open Access
A model argument for accurate EF
© Rayarao et al. 2016
- Published: 27 January 2016
- Standard Deviation
- Simultaneous Equation
- Internal Agreement
- Coupling Condition
- Improve Accuracy
CMR still suffers from several sources of inaccuracy in measuring LV volumes and EF. Typical standard deviations (SD) between readers for EF range from 4% - 7.5% (Quantification of LV function: Suinesiaputra A, et al. J Cardiovasc Magn Reson. 2015 Jul 28;17(1):63). Further, since the data range of agreement for 95% of data is 4SD (i.e. 16% - 30%), it is common practice to adjust EF based on a visual assessment. This presents several major problems in that there is no guarantee that visual EF is a good guide and that adjustments to EDV and ESV will result in the SV being adjusted correctly. Here we present a technique termed ‘Removing Endocardial Measured Overage Directionally using External Leverage' (REMODEL) that accomplishes intuitive simultaneous corrections of EF and SV.
For a group of patients (N = 107) we applied phase velocity mapping (PVM) to the aorta to calculate SV. Using previously described aortic coupling conditions, we also calculated EF from the aortic PVM data. These measures were used to estimate EDVest and ESVest using the following simultaneous equations:
EDVest = SV/EF
ESVest = (SV/EF) - SV
where SV and EF are derived from the aortic PVM data.
By using PVM for aortic calculation of SV and EF, it is possible to re-evaluate EDV and ESV making adjustments to LV contours in a systematic manner that simultaneously brings EF and SV into internal agreement between aortic and LV measures. This approach, which only requires a single additional PVM data set, has immediate clinical implication further improving accuracy and reproducibility of EF.
This article is published under license to BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated.