Cardiac MRI: development of a semiautomatic software to study left ventricular trabeculation

Left ventricular non-compaction is a rare cardiomyopathy with an incidence of 0,014 % in adult patients. Its prognosis remains little known. Untreated, it can lead to heart failure, cardioembolic events, tachyarrhythmia, heart transplant and death. Non compaction is suspected on echocardiography or CMR when a characteristic double layered aspect of the myocardium with a thick, non-compacted endocardial layer, prominent trabeculations and deep recesses are observed, but there is no gold standard for the diagnosis. Some have proposed 2D criteria based on ratios of lengths between compacted and non compacted layers evaluated by sonography or MRI. Jacquier and al. have proposed a quantification of the total amount of LV trabeculation on CMR but with a manual contouring including blood inside the trabeculae. Our purpose was the development of a semi-automatic software package to calculate the non-compacted mass that suppresses blood from the trabeculae and evaluates the total amount of compacted and non compacted mass. The feasibility of this trabeculation quantification algorithm was illustrated in multicenter, multivendor 1.5 and 3 T MRI. The software allows a precise and reproducible segmentation in about 15 min. The quantification software was compared with histology, and tested for accuracy and reproducibility in a mouse model of non-compaction. The software was tested in a large cohort of healthy subjects to provide the range of normal values of trabeculae across age and gender. Clinical validation on patients with non compaction is in progress. (author)