Diagnostic value of 3.0 T cardiac MRI in children with suspected myocarditis: multi-parameter analysis for the evaluation of acute and chronic myocarditis

Background Cardiac magnetic resonance (CMR) is an established tool for detection of myocarditis. However, no comprehensive data for CMR based on the “Lake Louise” criteria in pediatric myocarditis exists to date. Purpose To evaluate the value of multi-parameter CMR in children with suspected acute (AMC) and chronic myocarditis (CMC). Material and Methods We examined 73 pediatric patients with clinically suspected AMC (n = 25) and CMC (n = 48). We compared them to 17 controls. All individuals underwent CMR, including function analyses, T2 ratio, early gadolinium enhancement ratio (EGEr), and late gadolinium enhancement (LGE). Results In AMC, 19 (76%) patients were abnormal in any two of three parameters (T2 ratio, EGEr, and LGE). There was a significant difference between AMC and controls in LVEF (51.2% vs. 61.3%), mass (130.2 ± 14.0 vs. 120.5 ± 13.9 g), T2 ratio (1.96 ± 0.2 vs. 1.69 ± 0.13), and EGEr (4.1 ± 0.27 vs. 3.4 ± 0.39) ( P < 0.05). In CMC, 26 (54.1%) patients were abnormal in any two of three parameters. There was no significant difference between CMC and controls in LVEF and mass, but there was a statistical difference in T2 ratio (1.88 ± 0.18 vs. 1.69 ± 0.13) and in EGEr (3.93 ± 0.22 vs. 3.4 ± 0.39) ( P < 0.05). There was an increase in LVEF while both T2 ratio and EGEr significantly decreased ( P < 0.05) during follow-up of acute fulminant myocarditis. Conclusion Comprehensive CMR may serve as a powerful tool in children with suspected AMC. CMR in assessment of CMC may be valuable, but it is not satisfactory.

P632 Apical mass after acute myocardial infarction

Funding Acknowledgements No financial support 53-year-old male, with a personal history of high blood pressure and current smoking. He presented in the emergency department with typical chest pain. The initial electrocardiogram showed a ST segment elevation in DI and AVL leads. An emergency coronariography was performed showing a single vessel disease with two tandem lesions on the first diagonal, which were treated with pharmacoactive stents. An echocardiography was performed, showing a mild apicolateral hypokinesia, with good contractility of the remaing segments. In addition, a rounded, pediculated and mobile mass in the apex was observed; the mass was hyperechogenic compared to the myocardium. In this setting, the differential diagnosis should include thrombus in context of acute coronary syndrome (despite a small infarction with early revascularization and good contractility of the segments involved) vs. tumoral mass. Anticoagulant treatment was maintained and a cardiac magnetic resonance (MR) was performed. The MR showed an apical round mass of 11 mm, with hyperintense signal in both T1- and T2-enhanced sequences in comparison to normal myocardium; although no contrast uptake was observed in early gadolinium enhancement sequence, the mass showed homogeneous enhancement in the late enhancement images, both with optimal TI and with long T1. These findings were suggestive of a benign tumoral mass of atypical location. In addition, a small anterior subendocardial enhancement with preserved ejection fraction was observed. A control echocardiogram after 5 weeks of anticoagulant treatment showed no changes in either size or characteristics of the mass. After risk-benefit assessment and according to patient preferences, surgical resection of the mass was decided by a mini-thoracotomy approach. A surgical piece was obtained, described as a mobile pediculated tumour with a granulated surface and mucinous aspect. The postoperative period was uneventful. Subsequently, the pathological study confirmed the diagnosis of papillary fibroelastoma of atypical location. This case summarizes the usefulness of MR to characterize cardiac masses and, in particular, to differentiate tumours from thrombus. Although in this setting (recent myocardial infarction) an apical thrombus was initially suspected, the MR exam correctly identified a contrast enhanced mass, which ruled out acute thrombus and suggested benign tumour. Abstract P632 Figure.

Chronic Anthracycline-related Myocarditis Presenting as Diffuse Myocardial Calcification

In the setting of cardio-oncology, evaluation for myocarditis is a growing indication for cardiovascular magnetic resonance (CMR). Treatment-related side effects of cancer therapies comprise the majority of myocarditis cases in cardio-oncology, and these are often secondary to anthracyclines and even the newer class of immune checkpoint inhibitors. Cardiotoxicity from cancer therapy represents an increasingly recognized etiology of myocarditis and when detected, warrants prompt management changes. The conventional CMR evaluation for myocarditis includes modules for the left ventricular structure and function, early gadolinium enhancement, and late gadolinium enhancement. Newer CMR sequences including native T1 mapping and extracellular volume fraction offer improvement in diagnostic accuracy from conventional CMR methods. We present a case of subacute/ chronic myocarditis related to anthracycline therapy 4 months prior that was diagnosed only after incidental diffuse myocardial calcifications on pre-treatment computed tomography raised suspicion.