While CMR excels at detecting irreversible fibrosis, 18F-FDG-PET is exceptionally sensitive for detecting active, ongoing inflammation. FDG is a glucose analog taken up by highly metabolically active cells, notably the activated macrophages within nascent granulomas, mediated by glucose transporters (GLUTs). The major physiological hurdle in cardiac PET is the heart's native reliance on glucose. To suppress background physiologic myocardial glucose uptake and isolate the pathological inflammatory signal, rigorous dietary preparation is mandatory. Patients must undergo a prolonged fast (≥ 12 hours), frequently paired with a preceding high-fat, low-carbohydrate diet (and sometimes an unfractionated heparin bolus), to shift myocardial substrate utilization toward free fatty acids and suppress physiologic glucose uptake -- ensuring that any residual FDG signal reflects pathological inflammatory activity rather than normal myocardial metabolism.
Related RCIS terms
Study RCIS terms in context
Cardiac Codex turns definitions like this into a full study system: 177 lessons, 2,233 practice questions with explanations, blueprint-matched mock exams, and Cardiac Coach — an AI tutor grounded in this exact glossary you can ask from any lesson.
Get early access Back to the glossary →