The impact of simplified endocardial contouring on left ventricular volumetric assessment

To assess the impact of simplified endocardial contouring, performed manually and using semi-automated software, on left ventricular (LV) volumetric assessment.

Cardiovascular magnetic resonance (CMR) is the gold standard for LV volumetric assessment. Detailed tracing of the endocardial border, including papillary muscles and trabeculations, can be time consuming. In many centres it is clinical practice to simplify this and trace the general outline of the endocardial border instead. Such analysis means that all non-wall adherent trabeculations are included in the LV cavity rather than within the myocardium. We aimed to assess the impact of manual and semi-automated simplified endocardial contouring on the accuracy and reproducibility of LV volumetric assessment.

20 consecutive patients undergoing clinically indicated CMR imaging were included. SSFP cine images were obtained using a 1.5 T scanner (Siemens Avanto, Germany) and a 32-channel coil system. Images were independently analysed by 2 observers using 3 software packages; 1. CMRtools (UK) which includes a thresholding tool allowing detailed endocardial border tracing, used as the reference standard in this study; 2. Siemens Argus ("Argus")-simplified manual endocardial contouring; 3. Siemens Argus 4DVF ("4DVF")-semi-automated simplified endocardial contouring. 25% of scans were reanalysed to assess intra-observer reproducibility. Time taken for each analysis was recorded.

Simplified manual endocardial contouring is time saving and reproducible, however it significantly overestimates LV volumes and underestimates EF, which could have significant implications for clinical decision making. In our hands, the semi-automated simplified endocardial contouring software did not provide any advantages.