Measurement of myocardial extracellular volume using cardiac dual-energy computed tomography in patients with ischaemic cardiomyopathy: a comparison of different methods

To clarify the consistency and efficiency of four methods for myocardial extracellular volume (ECV) measurement (manual method using dual-energy iodine [manual ECV iodine ], manual method using subtraction [manual ECV sub ], automatic ECV iodine , automatic ECV sub ) in patients with ischaemic cardiomyopathy. Fifty patients with ischaemic cardiomyopathy who underwent coronary computed tomography angiography (CCTA) following dual-energy computed tomography (CT) with late iodine enhancement (LIE-DECT) were included. LIE with ischaemic patterns representing scarring could be detected using iodine maps in all patients. The global and remote ECVs of non-scarred myocardium were measured using four methods (manual ECV iodine , automatic ECV iodine , manual ECV sub , and automatic ECV sub ). The consistency and time cost of the four methods were analysed. There were no significant differences in the mean global ECVs or remote ECVs among the four methods ( p > 0.05). ECV iodine resulted in a lower Bland–Altman limit of agreement than that of ECV sub for both global and remote measurements. Intraclass correlation coefficients of the automatic and manual ECV iodine measurements demonstrated better concordance (0.804 and 0.859, respectively) than those of automatic and manual ECV sub (0.607 and 0.669, respectively) for both global and remote measurements. The measurement time for automatic ECV was less than that for manual ECV for both global and remote ECV measurements (all p < 0.001). ECV measurement using dual-energy iodine yielded good concordance, and the automatic method has the advantages of being simple and convenient, which can become a useful tool for quantification of myocardial fibrosis.