| ObjectiveViral myocarditis (VMC) was the commonest type of myocarditis in children. Endomyocardial biopsy was considered as the "gold standard" to diagnose VMC, the feature of invasiveness and low sensitivity limited its clinical application, however. The methods in the diagnosis of VMC nowadays included cardiac injury markers, electrocardiograms and echocardiography. Magnetic resonance imaging, a new kind of noninvasive medical imaging technology, had excellent resolution and no ionizing radiation. It was a multi-directional imaging and multi-parameter imaging, and also capable of Histopathological imaging by myocardial perfusion imaging and delayed enhancement examination. But little study about children was reported, this study aimed to determine the diagnostic value of myocardial perfusion imaging and delayed enhancement examination by CMR in children with VMC.Materials and MethodsChose28children from the Pediatric Cardiology Department of Provincial Hospital affiliated with Shandong University from July2011to March2013that had been diagnosed as viral myocarditis (18males and10female; age range,5-16years, and mean age,9.6years) as the VMC group,7children with primary dilated cardiomyopathy (5males and2female; age range,1.2-10years, and mean age,6.2years) as the group of DCM, and another13healthy children (8males and5female; age range,6-12years, and mean age,8.9years) as the control group. Cardiac injury markers(cTnT、CKMB-mas、and pro-BNP), electrocardiogram, transthoracic echocardiography were performed in all of the children before CMR imaging. All the children underwent CMR imaging, including morphology scanning, cine CMR imaging, CMR myocardial perfusion and delayed enhancement scanning. The results of CMR was compared with cardiac injury markers, electrocardiograms and echocardiography.5children with VMC reexamined CMR in recovery phase.Results1. All of the28children with VMC had histories of viral infections in the premorbid1-3weeks. Among the28cases,9children were diagnosed as severe VMC and the rest19children were diagnosed as common VMC.2. The youngest children with VMC was1.2years, and all the children were successfully and safely performed CMR imaging, no adverse reaction to the contrast agent and other complications occurred. Heart rate of all the children were under120bpm, the mean examination time was40min to a hour.3.19case with VMC had abnormality in CMR:(1)7cases with dilated heart,12cases with regional thinning myocardium,2cases with thickening interventricular septum;(2)8cases with reduced myocardial mobility,4cases with reduced left ventricular ejection fraction (44%-49%);(3)1case with high signal in T2-weighted image,17cases showed delayed-enhancement, the enhancement signals were located mostly in lateral and inferior wall of left ventricular, they were enhanced significantly and pervasively in severe VMC, while mildly and patchily in common VMC.4. The sensitivity of CMR delayed enhancement scan in children with VMC was significantly higher than in children with dilated cardiomyopathy (60.71%vs0%, P <0.01), and the sensitivity in severe VMC sensitivity was significantly higher than that of ordinary VMC (100%vs42.11%,P<0.01). The specificity was100%in VMC group.5. Among the children with ST-T changes in electrocardiogram,70%showed delayed enhancement signal in corresponding parts, while among the children with thinning myocardium or reduced the mobility in echocardiography,68.75%showed delayed enhancement signal in corresponding parts,6.5children with VMC re-examination CMR after their treatments,3cases’ delayed-enhancement signals disappeared while the other2cases’ became weaker than before.Conclusions1. CMR was a safely and effectively noninvasive mean to diagnose VMC.2. VMC performed expanded heart, regional thinning myocardium, reduced mobility, reduced left ventricular ejection fraction, high signal in T2weighted imaging and delayed enhancement signal in CMR.3. The specificity of CMR delayed enhancement examination in severe VMC was higher than the sensitivity in ordinary VMC.4. CMR delayed enhancement examination could dynamically observe the changes of myocardial inflammation, it can be used in the follow-up of VMC. |
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