Localized strain characterization of cardiomyopathy in Duchenne muscular dystrophy using novel 4D kinematic analysis of cine cardiovascular magnetic resonance

Fig. 1. 3D + time CMR localized strain analysis A 3D + time cardiovascular magnetic resonance (CMR) image created from 2D cine short -axis image stack. B, C 48 point left ventricular (LV) feature-tracking schematic with example images in short-axis (D) and long axis (E) views from a MATLAB-based graphical user interface. Example circumferential (Ecc; F), longitudinal (Ell; G), radial (Err; H), surface area (Ea; I) colorized strain maps at peak systole derived from 3D + time CMR images of a Duchenne muscular dystrophy (DMD) patient from MATLAB feature-tracking analysis. F–I also correspond to Additional files 1, 2, 3, 4. Scale bar = 1 cm

Fig. 2. 3D + time CMR- derived localized Ecc peak circumferential strain and systolic strain rate can discriminate between DMD (n = 43) and healthy control (n = 25) subjects. A, B Schematic representation of regional circumferential strain (Ecc). C Example CMR image slice depicting feature-tracked endocardium (blue) and epicardium (green) D Localized peak Ecc and E systolic strain rate (normalized to cardiac cycle) shows significant differences between healthy control subjects and DMD patients- particularly in the basal region for peak strain and in all regions for systolic strain rate. *p < 0.05, **p < 0.01, ****p < 0.001, error bars depict median and interquartile range

Fig. 3. 3D + time CMR-derived localized systolic strain rate can discriminate between DMD patients (n = 43) and healthy control (n = 25) subjects. A, B Schematic representation of localized longitudinal strain (Ell) and strain rate. C Example 4D CMR long-axis image slice depicting feature-tracked endocardium (blue) and epicardium (green), D Localized peak Ell between DMD patients and healthy control subjects less significant than peak Ell, however E Ell systolic strain rate (normalized to cardiac cycle) shows significant differences between healthy control subjects and DMD patients in all regions. **p < 0.01, ***p < 0.001, error bars depict median and interquartile range

Fig. 4. 3D + time CMR localized radial strain significantly different in DMD vs. Control patients. A Short-axis schematic representation of radial strain (Err). B Healthy control polar plot with overlaid slice-level polar map and 3D LV colorized endocardium representation of localized Err. C Localized and global peak Err significantly different between healthy control subjects and DMD patients. D Mild, E moderate, and F severe (as determined by LV ejection fraction) DMD patient examples of 17 segment polar and 3D colorized LV representations of peak Err. Scale bar = 1 cm. **p < 0.01, ****p < 0.001, error bars depict median and interquartile range

Fig. 5. 3D + time CMR localized surface area strain significantly different in DMD vs. healthy control subjects. A Short-axis schematic representation of surface area strain (Ea) B Healthy control polar plot with overlaid slice-level polar map and 3D LV colorized endocardium representation of local Ea. C Localized and global peak Ea significantly different between healthy control subjects and DMD patients. D Mild, E moderate, and F severe (as determined by LVEF) DMD patient examples of 17 segment polar and 3D colorized LV representations of peak Ea. Scalebar = 1 cm. *p < 0.05, **p < 0.01, ****p < 0.001, error bars depict median and interquartile range

Fig. 6. 3D + time CMR-derived localized strain and strain rate comparison for discriminating DMD cardiomyopathy (CMP) (n = 43) vs. healthy controls (n = 25) subjects using Wilson/Brown method for receiver operator characteristic curve analysis

Fig. 7. Regional strain differentiates mild, moderate, and severe DMD CMP from healthy control subjects. A Stratification paradigm for healthy controls (n = 25) and DMD CMP (n = 43) patients between those without myocardial delayed enhancment (MDE) and an LVEF >55% (Group A, n = 15) those with MDE and LVEF > 55% (Group B, n = 15) and those with MDE and LVEF < 55% (Group C, n = 13). B–D) Basal region peak circumferential strain (Ecc; B), radial strain (Err; C), and surface area strain (Ea; D) shows differences between healthy controls and DMD CMP groups A, B, and C. Basal region systolic strain rates for Ecc (E), Err (F), and Ea (G), show significant differences between healthy controls and DMD CM groups A, B, and C. *p < 0.05, **p < 0.01,***p < 0.001 ****p < 0.001, error bars depict median and interquartile range