Delayed Dual-Time Point Imaging Protocol Improving Myocardial Uptake of 18-Fluorine Flouro Deoxyglucose (18F-FDG) During Viability Screening of Diabetes Mellitus Type 2 Patients Using Integrated Positron Emission Tomography/Computed Tomography (PET/CT) Imaging

Aims: To investigate the effect of delayed imaging protocol and hypoglycemic agent on quantitative values obtained during myocardial viability 18F-FDG PET/CT assessment.

Presentation of Case: Mr. A, a 72 year-old man, Madam B, a 73 year-old woman and Madam C, a 64 year-old woman, presented to the Centre for Diagnostic Nuclear Imaging, Universiti Putra Malaysia for myocardial viability assessment. All were diagnosed Diabetes Mellitus type II on oral hypoglycemic agent.

Discussion: Our study showed an increased 18F-FDG uptake in the wall of LV after the delayed protocol was applied to the patients. One hour time elapsed before 18F-FDG injection is to allow optimal level of niacin in the blood for its action to lower the plasma FFA levels and encourage myocardial preference towards glucose metabolism. Oral glucose loading is given to stimulate insulin secretion and increase glucose utilization as the metabolic substrate. The approach of premedicating nicotinic acid like niacin can be a reliable hypolipidemic agent in shifting myocardial metabolism to glucose oxidative pathway in 18F-FDG PET/CT myocardial viability assessment. Delayed enhancement imaging has been shown to be effective, in both animals and humans, in identifying the presence, location, and extent of acute and chronic myocardial infarction in patients with ischemic cardiomyopathy. Furthermore, this technique may also be useful in assessing myocardial injury in patients with non-ischaemic heart disease.

Conclusion: Delayed imaging is superior to early imaging. The improvement of the image quality leads to accurate assessment of the viable or non-viable myocardium.