## 3 Results
### CMR Characteristics
#### 3.2.2 Strain Measurements  
An example of strain measurements using the CMR-FT technique of a DMD patient is illustrated in Figure 2. As Table 3 indicates, the CMR-FT strain measurements were considerably lower than those of the healthy controls. All \(p\)-values were lower than 0.001. The average GCS found was \(-\)16.12 \(\pm\) 3.55%, IQR [\(-\)19.40, \(-\)13.00] % vs. \(-\)19.34 \(\pm\) 4.48%, IQR [\(-\)21.70, \(-\)16.40] %. The GLS was reduced in the DMD patients in comparison to the healthy controls: (\(-\)13.79 \(\pm\) 5.28%, IQR [\(-\)16.90, \(-\)11.40] % vs. -17.13 \(\pm\) 5.94%, IQR [\(-\)18.40, \(-\)12.50] %). The same behavior was maintained for the GRS of the DMD patients: 27.49 \(\pm\) 2.44%, IQR [23.20, 35.90] % and for the healthy controls: 31.69 \(\pm\) 2.53%, IQR [25.90, 35.00] %. ROC curve analysis was applied to evaluate the capability of global strain measurements to differentiate the DMD patients from the healthy controls (Figure 3 and Table 4). The GCS, GLS, and GRS performed well, providing areas under the curve (AUC) values of 0.93, 0.98, and 0.94, respectively. The values of \(p\)-value, sensitivity, and specificity of the different global strain measurements are presented in Table 4. Among these parameters, the GCS exhibited the highest sensitivity (86%), with a specificity of 90%, while the GLS demonstrated the highest specificity (96%), with a sensitivity of 95%. Moreover, the GRS showed specificity and sensitivity levels surpassing 90%. The AUC for the GLS was the greatest (0.98, \(p\)-value = 0.001), despite the GLS to GRS on the long axis (LAX) exhibiting a gradual increase in the AUC.  
\begin{table}
\begin{tabular}{c c c c c} \hline \hline
**Variable** & **AUC (95\% CI)** & \(p\)**-Value** & **Sensitivity (\%)** & **Specificity (\%)** \\ \hline GCS (\%) & 0.93 & 0.003 & 86 & 90 \\ GLS (\%) & 0.98 & 0.001 & 96 & 95 \\ GRS (\%) & 0.94 & 0.046 & 90 & 93 \\ \hline \hline \end{tabular}
\end{table}
Table 4: ROC analysis results.  
\begin{table}
\begin{tabular}{c c c c} \hline \hline
**Variable** & **DMD (_n = 28_)** & **Controls (_n = 20_)** & \(p\)**-Value** \\ \hline Subject characteristics & & & \\ Age (year) & 10.56 \(\pm\) 1.79 & 11.30 \(\pm\) 2.71 & 0.057 \\ Weight (kg) & 31.36 \(\pm\) 6.45 & 42.85 \(\pm\) 12.73 & **0.001** \\ Height (cm) & 133.29 \(\pm\) 10.56 & 148.45 \(\pm\) 14.74 & **<0.001** \\ BSA (m\({}^{2}\)) & 1.06 \(\pm\) 0.15 & 1.34 \(\pm\) 0.25 & **<0.001** \\ CMR characteristics of LV & & & \\ Functional & & & \\ LVEDV/BSA (mL/m\({}^{2}\)) & 73.07 \(\pm\) 10.74 & 80.09 \(\pm\) 6.80 & 0.887 \\ LVESV/BSA (mL/m\({}^{2}\)) & 33.07 \(\pm\) 5.58 & 30.87 \(\pm\) 4.69 & 0.150 \\ SV/BSA (mL/m\({}^{2}\)) & 41.96 \(\pm\) 7.65 & 48.48 \(\pm\) 7.06 & 0.005 \\ Myocardial mass/BSA (g/m\({}^{2}\)) & 40.54 \(\pm\) 4.80 & 40.20 \(\pm\) 5.25 & 0.820 \\ LVEF (\%) & 56.14 \(\pm\) 3.51 & 61.60 \(\pm\) 4.66 & **0.003** \\ Geometry & & & \\ ED wall thickness (mm) & 6.72 \(\pm\) 2.71 & 8.18 \(\pm\) 1.76 & **<0.001** \\ ES wall thickness (mm) & 7.38 \(\pm\) 2.75 & 8.89 \(\pm\) 2.52 & **<0.001** \\ Wall thickening (\%) & 55.85 \(\pm\) 8.98 & 72.83 \(\pm\) 7.45 & **<0.001** \\ \hline \hline \end{tabular} BSA: body surface area; LVESV: left ventricle end-systolic volume; LVEDV: left ventricle end-diastole volume; SV: stroke volume; ED: end diastole; ES: end-systolic; LVEF: left ventricle ejection fraction; data are presented as means \(\pm\) SD (significant \(p\)-values are indicated in bold).  
\end{table}
Table 2: Subjects’ demographic, clinical, and CMR characteristics.  
\begin{table}
\begin{tabular}{c c c c} \hline \hline
**Variable** & **DMD (_n = 28_)** & **Controls (_n = 20_)** & \(p\)**-Value** \\ \hline GCS (\%) & \(-\)16.12 \(\pm\) 3.55 & \(-\)19.34 \(\pm\) 4.48 & **<0.001** \\ GLS (\%) & \(-\)13.79 \(\pm\) 5.28 & \(-\)17.13 \(\pm\) 5.94 & **<0.001** \\ GRS (\%) & 27.49 \(\pm\) 2.44 & 31.69 \(\pm\) 2.53 & **<0.001** \\ \hline \hline \end{tabular} (Significant \(p\)-values are indicated in bold).  
\end{table}
Table 3: Left ventricular myocardial strain parameters of subjects.