An increase in glycolysis in a region on PET indicates which condition?

• A. Normal tissue
• B. Inflammation
• C. Hypoperfusion
• D. Malignancy and tumors

Answer: (D)

FDG-PET detects glucose metabolism. Tumor cells often upregulate glycolysis to meet energy and biosynthetic needs, a phenomenon known as the Warburg effect, so they take up more FDG and show higher signal on PET. This increased glycolysis is a hallmark associated with malignancy and tumors, making it the most consistent explanation among the options. Normal tissue generally has lower uptake, and hypoperfusion tends to reduce tracer delivery, leading to less uptake. Inflammation can also raise uptake due to activated immune cells, but the pattern and degree are typically less definitive than in malignancy.