Value of Cardiac Magnetic Resonance Fractal Analysis Combined With Myocardial Strain in Discriminating Isolated Left Ventricular Noncompaction and Dilated Cardiomyopathy

Background: Excessive trabeculation is present in isolated left ventricular noncompaction (LVNC) and dilated cardiomyopathy (DCM), which sometimes makes the differentiation between these two difficult. Fractal dimension (FD) is a unitless measure value of how completely the object fills space, which can assess the extent of myocardial trabeculae quantitatively. Purpose: To compare the trabeculae features and myocardial strain derived from cardiac MR between LVNC and DCM. Study Type: Respective case–control series. Population: In all, 35 LVNC patients and 30 DCM patients were enrolled, and 20 healthy volunteers were selected as a control group. Field Strength/Sequence: 5 T with 8-channel phased-array cardiac receiver coil including steady-state free precession cine imaging. Assessment: The degree of left ventricular trabeculation was evaluated by a semiautomatic tool based on fractal analysis. Myocardial deformation was assessed by feature tracking. Statistical Tests: Independent samples Student's t-test, Mann–Whitney U-test, receiver operating characteristics (ROC) curves, and Spearman's rank coefficient were conducted. Results: Max apical FD and mean global FD were higher in the LVNC group than in the DCM group (1.433 ± 0.074 vs. 1.341 ± 0.062, P < 0.001; 1.323 ± 0.036 vs. 1.267 ± 0.041, P < 0.001, respectively). For diagnosing LVNC, max apical FD was 1.392 (area under the curve [AUC] = 0.881, 95% confidence interval [CI]: 0.804–0.957), and the cutoff value of mean global FD was 1.283 (AUC = 0.895, 95% CI: 0.828–0.961). The global peak longitudinal strain value of the left ventricle (GPLS) showed significant differences between the LVNC group and DCM group [–6.49 (–11.41, –4.90) vs. –4.61 (–5.87, –3.61), P = 0.006]. The diagnostic accuracy for LVNC is highest when using FDs in coordination with GPLS (AUC = 0.93, 95% CI: 0.86–0.98, P < 0.001). Data Conclusion: Fractal analysis provides a quantitative measurement of myocardial trabeculation. The combination of fractal analysis with myocardial strain provides a novel biomarker in distinguishing LVNC from DCM. Level of Evidence: 3. Technical Efficacy Stage: 2. J. Magn. Reson. Imaging 2019;50:153–163.