Cardiac magnetic resonance in giant cell myocarditis: a matched comparison with cardiac sarcoidosis

Abstract

Aims Giant cell myocarditis (GCM) is an inflammatory cardiomyopathy akin to cardiac sarcoidosis (CS). We decided to study the findings of GCM on cardiac magnetic resonance (CMR) imaging and to compare GCM with CS. Methods and results CMR studies of 18 GCM patients were analyzed and compared with 18 CS controls matched for age, sex, left ventricular (LV) ejection fraction and presenting cardiac manifestations. The analysts were blinded to clinical data. On admission, the duration of symptoms (median) was 0.2 months in GCM vs. 2.4 months in CS (P = 0.002), cardiac troponin T was elevated (>50 ng/L) in 16/17 patients with GCM and in 2/16 with CS (P < 0.001), their respective median plasma B-type natriuretic propeptides measuring 4488 ng/L and 1223 ng/L (P = 0.011). On CMR imaging, LV diastolic volume was smaller in GCM (177 ± 32 mL vs. 211 ± 58 mL, P = 0.014) without other volumetric or wall thickness measurements differing between the groups. Every GCM patient had multifocal late gadolinium enhancement (LGE) in a distribution indistinguishable from CS both longitudinally, circumferentially, and radially across the LV segments. LGE mass averaged 17.4 ± 6.3% of LV mass in GCM vs 25.0 ± 13.4% in CS (P = 0.037). Involvement of insertion points extending across the septum into the right ventricular wall, the “hook sign” of CS, was present in 53% of GCM and 50% of CS. Conclusion In GCM, CMR findings are qualitatively indistinguishable from CS despite myocardial inflammation being clinically more acute and injurious. When matched for LV dysfunction and presenting features, LV size and LGE mass are smaller in GCM.

Diagnosis and Management of Cardiac Sarcoidosis: A Scientific Statement From the American Heart Association

“…However, there are no patterns of LGE that are sufficient for the diagnosis CS; thus, even when patients have pathology-frequent LGE, cardiac or extracardiac tissue confirmation may still be helpful because other processes (eg, giant-cell myocarditis) may have CMR findings indistinguishable from CS. 31 Furthermore, CMR interpretation may be subject to interreader interpretation due to nonspecific findings for CS. 32 Last, the absence of LGE does not fully exclude CS because early cardiac involvement may exist before the presence of LGE on imaging.…”

Giant cell myocarditis with prolonged cardiac standstill after drug‐induced hypersensitivity syndrome: a case report

“…Although cardiovascular magnetic resonance imaging may be useful to raise the clinical suspicion of GCM and cardiac sarcoidosis, many patients, such as our case, are too unstable for cardiovascular magnetic resonance imaging. 15 The last cardiac specimen confirmed that most of the cardiac tissue had been replaced by granulation tissue, which appeared to be a chronic stage and ‘clinical cardiac death’.…”

Unraveling the Uncommon: A Case Report of Giant Cell Myocarditis and Examination of Existing Literature

“…CMR appearance of IGCM and cardiac sarcoidosis is highly similar, including evidence of multifocal late gadolinium enhancement and the presence of the “hook sign” (prominent involvement of the anteroseptal and inferoseptal insertion points of the right ventricle, with direct and contiguous extension across the septum into the right ventricle), which makes differentiating between the 2 rare entities solely based on CMR challenging [ 16 , 17 ]. Furthermore, CMR cannot differentiate IGCM from cardiac sarcoidosis, which has similar clinical manifestations to IGCM, such as heart failure, heart block, and ventricular tachyarrhythmias [ 18 ]. Similarly, a TTE can be used as the first-line diagnostic tool in patients with clinically suspected myocarditis, to strengthen the initial clinical suspicion and rule out other possible differential diagnosis.…”