Cardiac magnetic resonance visualizes acute and chronic myocardial injuries in myocarditis

Our objective was to evaluate the ability of CMR to visualize myocardial injuries over the course of myocarditis. We studied 42 patients (39 males, 3 females; age 37 ± 14 years) with myocarditis during the acute phase and after 12 ± 9 months. CMR included function analyses, T2-weighted imaging (T2 ratio), T1-weighted imaging before and after i.v. gadolinium injection (global relative enhancement; gRE), and late gadolinium enhancement (LGE). In the acute phase, the T2 ratio was elevated in 57%, gRE in 31%, and LGE was present in 64% of the patients. In 32 patients (76%) were any two (or more) out of three sequences abnormal. At follow-up, there was an increase in ejection fraction (57.4 ± 11.9% vs. 61.4 ± 7.6; P < 0.05) while both T2 ratio (2.04 ± 0.32 vs. 1.70 ± 0.28; P < 0.001) and gRE (4.07 ± 1.63 vs. 3.11 ± 1.22; P < 0.05) significantly decreased. The LGE persisted in 10 patients. Dilated cardiomyopathy was present in 3 patients and 4 patients received a defibrillator or a pacemaker. A comprehensive CMR approach is a useful tool to visualize myocardial tissue injuries over the course of myocarditis. CMR may help to differentiate acute from healed myocarditis, and add information for the differential diagnoses

Left ventricular T2 distribution in Duchenne Muscular Dystrophy

<p>Abstract</p> <p>Background</p> <p>Although previous studies have helped define the natural history of Duchenne Muscular Dystrophy (DMD)-associated cardiomyopathy, the myocardial pathobiology associated with functional impairment in DMD is not yet known.</p> <p>The objective of this study was to assess the distribution of transverse relaxation time (T2) in the left ventricle (LV) of DMD patients, and to determine the association of myocardial T2 heterogeneity to the severity of cardiac dysfunction. DMD patients (n = 26) and normal control subjects (n = 13) were studied by Cardiovascular Magnetic Resonance (CMR). DMD subject data was stratified based on subject age and LV Ejection Fraction (EF) into the following groups: A (<12 years old, n = 12); B (≥12 years old, EF ≤ 55%, n = 8) and C (≥12 years old, EF = 55%, n = 6). Controls were also stratified by age into Groups N1 (<12 years, n = 6) and N2 (>12 years, n = 5). LV mid-slice circumferential myocardial strain (ε_cc) was calculated using tagged CMR imaging. T2 maps of the LV were generated for all subjects using a black blood dual spin echo method at two echo times. The Full Width at Half Maximum (<it>FWHM</it>) was calculated from a histogram of LV T2 distribution constructed for each subject.</p> <p>Results</p> <p>In DMD subject groups, <it>FWHM </it>of the T2 histogram rose progressively with age and decreasing EF (Group A <it>FWHM</it>= 25.3 ± 3.8 ms; Group B <it>FWHM</it>= 30.9 ± 5.3 ms; Group C <it>FWHM</it>= 33.0 ± 6.4 ms). Further, <it>FWHM </it>was significantly higher in those with reduced circumferential strain (|ε_cc| ≤ 12%) (Group B, and C) than those with |ε_cc| > 12% (Group A). Group A <it>FWHM </it>was not different from the two normal groups (N1 <it>FWHM </it>= 25.3 ± 3.5 ms; N2 <it>FWHM</it>= 24.0 ± 7.3 ms).</p> <p>Conclusion</p> <p>Reduced EF and ε_cccorrelates well with increased T2 heterogeneity quantified by <it>FWHM</it>, indicating that subclinical functional impairments could be associated with pre-existing abnormalities in tissue structure in young DMD patients.</p