Feature-Tracking MRI Fractal Analysis of Right Ventricular Remodeling in Adults with Congenitally Corrected Transposition of the Great Arteries

Purpose: To assess a recently available technique for quantification of right ventricular (RV) trabeculae that is based on fractal analysis performed by using cardiac MRI feature tracking, in patients with congenitally corrected transposition of the great arteries (cc-TGA). / Materials and Methods: A total of 19 patients (eight men, 11 women; mean age, 35 years ± 10 [standard deviation]) with consecutive cc-TGA who underwent cardiac MRI were enrolled in the study. For analysis, patients were divided into two groups: six patients (four men, two women; mean age, 34 years ± 14) with an end-systolic RV volume index higher than 72 mL/m2 (indicative of adverse RV remodeling) and 13 patients (four men, nine women; mean age, 36 years ± 9) in whom this index was lower than or equal to 72 mL/ m2 (indicative of adapted RV). The following outcomes were quantified in the midsection of the RV: fractional fractal dimension (FD) and diastolic FD, circumferential strain, and radial strain. Receiver operating characteristic (ROC) analysis was performed to determine the cutoff FD values for the detection of adverse RV remodeling. Correlations among fractional FD, diastolic FD, circumferential strain, and radial strain were calculated by using Pearson correlation coefficient (r) analysis. / Results: The following ROC values were identified for fractional and diastolic FD: cutoff, 0.09 and 1.39, respectively; area under the ROC curve, 0.95 and 0.68, respectively; sensitivity, 1.00 and 0.33, respectively; and specificity, 0.92 and 1.00, respectively. Fractional FD correlated with circumferential strain and radial strain (r = −0.70 and 0.69, respectively; P <.01), as did diastolic FD (r = 0.37 and −0.38, respectively; P ,<.05). / Conclusion: The fractional FD derived from cardiac MRI feature-tracking analysis correlates with adverse RV remodeling, including a changed strain pattern and trabeculae, in patients with cc-TGA.[Key Points] / ・In patients with congenitally corrected transposition of the great arteries, the fractional fractal dimension derived by using featuretracking MRI, as compared with the conventional diastolic fractal dimension, facilitates a more accurate diagnosis of the development of right ventricular trabeculae owing to adverse remodeling. / ・ Fractal analysis performed by using feature-tracking MRI is a robust analytical method with high reproducibility. / ・ As fractal analysis performed with feature-tracking MRI does not require additional manual processing, it can be easily included with strain analysis in cardiac workflow analysis in clinical practice