Seeking clarity: Insights from a highly effective preparation protocol for suppressing myocardial glucose uptake for PET imaging of cardiac inflammation

Excerpt

As ¹⁸F-fluorodeoxyglucose positron emission tomography (¹⁸F-FDG PET) is increasingly used for the detection of pathologic myocardial inflammation, a growing body of research has focused on improving imaging quality by seeking strategies to more successfully suppress background myocardial uptake of ¹⁸F-FDG, a radioactive glucose analogue. Both inflammatory cells and normal myocytes are highly metabolically active. However, unlike inflammatory cells, which constitutively rely on glucose for metabolism, normal myocytes are able to use either glucose or free fatty acids to meet their metabolic demands, depending on their current metabolic state.1,2 As such, patients must undergo preparation to shift background myocardial metabolism toward free fatty acids prior to radiotracer injection in order to effectively visualize pathologic inflammatory ¹⁸F-FDG uptake within the heart. To achieve this, a recent joint Society of Nuclear Medicine and Molecular Imaging-American Society of Nuclear Cardiology (SNMMI-ASNC) consensus statement provides broad rather than specific recommendations for patient preparation as the existing literature describes markedly heterogeneous protocols with no consensus on what defines adequate suppression.3,4 While there are clearly multiple ways to minimize myocyte glucose utilization, further insights are needed to develop an evidence-based, optimized protocol that can be broadly implemented across sites to maximize the utility of this imaging technique. …