Patterns of [18F]FDG myocardial uptake in oncology patients as a predictor of myocardial ischaemia on stress myocardial perfusion imaging

Background: There is variable cardiac uptake observed on oncological ¹⁸F-fludeoxyglucose ([¹⁸F]FDG) positron emission/computed tomography (PET/CT). The main purpose of this study is to evaluate patterns of overnight fasting myocardial [¹⁸F]FDG uptake in oncological PET/CT and analyse the relationship between myocardial [¹⁸F]FDG uptake and myocardial ischaemia on stress single-photon emission CT (SPECT) myocardial perfusion imaging (MPI).

Material and methods: A total of 362 subjects underwent both oncological PET/CT and stress SPECT MPI within 3 months of each other. Subjects with focal-mass-like [¹⁸F]FDG myocardial uptake raising the suspicion of cardiac metastasis and subjects with coronary artery disease (CAD) were excluded. The myocardial [18F]FDG uptake was classified into four patterns.

Results: Abnormal SPECT MPI was noted in 91 (25%) patients; 220 (61%) patients had completely absent [18F]FDG uptake, 80 (22%) had diffuse [¹⁸F]FDG uptake, 39 (11%) had focal on diffuse [¹⁸F]FDG uptake, and 23 (6%) had focal or regional myocardial [¹⁸F]FDG uptake, the regional [¹⁸F]FDG myocardial uptake was the most predictive of myocardial ischaemia on SPECT MPI, and there were positive associations between age, sex, hypertension, tobacco smoking, hypercholesterolemia, and left ventricular ejection, a fair agreement was noted between the focal or regional FDG uptake and presence of ischaemia on SPECT, K = 0.394 (95% CI 0.164 to 0.189).

Conclusions: Based on the presented findings, the physiological myocardial [¹⁸F]FDG uptake in fasting oncology patients is variable. The regional myocardial [¹⁸F]FDG uptake pattern is the most frequent pattern associated with myocardial ischaemia on stress SPECT MPI, however, the agreement between regional FDG uptake and presence of ischaemia on SPECT is fair.