In-vivo MRI and in-vivo electro-anatomical voltage map characteristics of infarct heterogeneity in a swine model

Abstract

The arrhythmogenic substrate in patients with prior myocardial infarct (MI) is located at the border zone, BZ. In this study we correlated the BZ identified by two methods: electro-anatomical voltage mapping (EAVM) and a novel MRI method, multi-contrast late enhancement (MCLE). A pre-clinical porcine model with chronic MI was used to characterize BZ via MRI and EAVM. Results focus on the comparison between scar percentage and BZ percentage identified by each method. The correlation coefficient for BZ percentage between the two methods was 0.74 with a p-value of less the 0.0001. Bland-Altman plots were also used to compare between the two methods (slope of 0.83 ± 0.045). For a case of subtle infarct, there was only 1.3% infarct identified on EAVM compared to 22.2% on the corresponding slice on MCLE. The percentage of infarct on MCLE in subtle infarct does not relate to percentage of infarct in EAVM. Future registration between T(1) maps and EAVM will permit a quantitative comparison of MRI and EAVM measures.

Probability mapping of scarred myocardium using texture and intensity features in CMR images

“…Recently, Shokrollahi et al  was able to divide the scarred myocardium of animals into core and gray zones using fuzzy clustering algorithm and validated the results using in-vivo electro-anatomical voltage mapping [6]. Some previous publications reported automatic segmentation of scarred myocardium in late enhanced magnetic resonance images [7-9].…”

“…To our knowledge, visualization of the heterogeneous nature of the myocardium is mostly based on thresholding methods described in the literature where thresholds are defined at intensity levels corresponding to some percentage of the maximum intensity level inside the scar area [ 1 - 3 ]. Recently, Shokrollahi et al was able to divide the scarred myocardium of animals into core and gray zones using fuzzy clustering algorithm and validated the results using in-vivo electro-anatomical voltage mapping [ 6 ]. Some previous publications reported automatic segmentation of scarred myocardium in late enhanced magnetic resonance images [ 7 - 9 ].…”