Background/Purpose : Cardiovascular disease (CVD) is a leading cause of death in patients with SLE. Lupus patients have a 2-3 fold increased risk of heart failure compared to age matched controls. Although the mechanisms remain unclear, lupus myocarditis (LM) has been proposed as a contributor. ¹⁸F-Fluoro-Deoxyglucose Positron Emission Computed Tomography (FDG-PET/CT) imaging has emerged as a novel modality to visualize myocardial inflammation in rheumatic diseases. The current study discusses our experience with FDG-PET/CT scanning in LM.

Methods: A total of eight SLE patients diagnosed with LM by FDG-PET/CT are described in this series. Demographics, SLE-specific characteristics, and CVD risk factors were ascertained. Coronary artery disease was evaluated by the Agatston coronary calcium score and/or coronary catheterization.

Results: Eight SLE patients (mean age 43±12 years) seen at the Lupus Center for complaints of chest pain 4 (50%), intermittent shortness of breath 2 (25%) or palpitations 2 (25%) followed from November 2015 to February 2016, underwent cardiac FDG-PET/CT for evaluation of LM. Six patients were female, 4/8 were Hispanic and 4/8 were non-Hispanic Black. The median SLEDAI-2K and SLICC SDI scores were 5 (2-11) and 1.5 (0-2), respectively. Mean SLE disease duration prior to the diagnosis of LM was 11±6 years. One patient had hypertension and diabetes, and 3 patients were former or current smokers. Of the 8 patients, 1 had a history of pericarditis and 5 had prior severe lupus activity and organ involvement: 4 had lupus nephritis and 1 had CNS lupus. All patients were ANA positive, 7 ds-DNA+ and 5 were anti-SSA antibody positive. None of the patients had anti-phospholipid antibody syndrome or APL antibodies. One patient had elevated troponins and elevated pro-BNP. Electrocardiographic abnormalities were noted in all patients with 5 having non-specific ST-T changes and sinus tachycardia. Interestingly, only 5 patients had echocardiographic abnormalities: pericardial effusion in 3 (38%), global hypokinesis in 2 (25%) and valvular abnormalities 2 (25%). The mean ejection fraction was 41±16% (Table 1). On cardiac FDG-PET/CT imaging, all patients had diffuse myocardial uptake (Figure 1).

Conclusion: These data propose that cardiac FDG-PET/CT imaging has higher sensitivity than 2-D echocardiography in detecting myocardial inflammation in SLE and support the use of FDG-PET/CT in the diagnosis of myocarditis in SLE. Table 1. Diagnostic Findings of SLE patients with FDG-PET/CT diagnosed myocarditis (n=8).

  Figure 1. Transverse and Coronal views of ¹⁸F-FDG-PET/CT imaging of Lupus Myocarditis showing septal, lateral and inferior uptake.