Objectives: Primary cardiac manifestation is a common complication of systemic sclerosis (SSc) with poor prognosis. The aim of the current study was to detect potential myocardial inflammation present in asymptomatic SSc patients by 18F-FDG-PET/CT and to investigate its relationship with early signs of myocardial dysfunction as detected by 2D speckle tracking echocardiography (2DSTE).
Methods: Sixteen consecutive patients with SSc and 9 control patients without clinical evidence of cardiac involvement were enrolled in the study. On 18F-FDG-PET acquired images blood-pool normalised SUV ratio and heterogenity index (HI: standard deviation of SUV divided with mean SUV) were calculated. Within 24 hours all SSc patients underwent 2DSTE strain analysis.
Results: Eight of 16 SSc patients were found to be visually PET-positive and showed significantly higher myocardial 18F-FDG SUV ratio (1.78±0.74 vs. 0.98±0.03; p<0.05) and heterogenity index (0.13±0.02 vs. 0.05±0.02; p<0.001) as compared to the control group. FDG-PET/CT derived values did not differ significantly between visually PET-negative (8/16) and control patients (SUV ratio: 0.98±0.05 vs. 0.98±0.03; HI: 0.05±0.01 vs. 0.05±0.02). Global left ventricular longitudinal strain values did not differ significantly between PET-positive and negative patients (17.18±3.49% vs. 17.59±3.65%).
Conclusions: Myocardial inflammation, as a potential sign of early cardiac involvement can be detected by 18-FDG-PET/CT in a considerable percentage of systemic sclerosis patients presenting without cardiac symptoms.