First experience of simultaneous PET/MRI for the early detection of cardiac involvement in patients with Anderson-Fabry disease

Purpose Anderson-Fabry disease (AFD) is a X-linked lysosomal storage disorder associated with severe multi-organ dysfunction and premature death. Early diagnosis and treatment strategies play a key role for patient outcome. We investigated the potential role of hybrid positron emission tomography (PET)-magnetic resonance (MR) imaging in the assessment of early cardiac involvement in AFD patients. Methods Thirteen AFD patients without cardiac symptoms and with normal left ventricular (LV) function underwent simultaneous cardiac PET-MR imaging after administration of 18F-fluorodeoxyglucose (FDG). Cardiac FDG uptake was quantified by measuring the standardized uptake value in 17 myocardial segments in each subject. Coefficient of variation (COV), which equals the standard deviation of uptake divided by the average uptake of 17 segments, was calculated as an index of heterogeneity in the heart. Results Six patients exhibited focal late gadolinium enhancement (LGE) as expression of intra-myocardial fibrosis and 4 of them had also positive short inversion time inversion recovery (STIR) sequences. All patients with LGE and positive STIR sequences showed focal FDG uptake in the corresponding myocardial segments, as expression of inflammation. Of the 7 patients with negative LGE and STIR images, 5 showed homogeneous FDG cardiac uptake, whilst the remaining 2 patients showed heterogeneous FDG uptake. The COV value was significantly greater patients with focal FDG uptake (0.25±0.02) than in those without (0.14±0.07, p<0.01). Conclusion PET-MR imaging is clinically feasible for the early detection of cardiac involvement in patients with AFD. Further studies evaluating the role of hybrid PET-MR in disease management in larger patients population are warranted.