In PET-CT using 18F-FDG, the standard uptake value (SUV) measures glucose metabolism. Physiologically, which organ normally shows the HIGHEST 18F-FDG uptake and can mimic pathology?

• A Liver
• B Spleen
• C Brain cortex ✓
• D Lung

Explanation

The brain cortex (grey matter) normally shows the highest physiological 18F-FDG uptake of any organ because neurons are obligate glucose consumers with high glucose transporter (GLUT1/GLUT3) expression and hexokinase activity. This can obscure small brain metastases. Other organs with high physiological uptake that can cause interpretive pitfalls: myocardium (variable, high in fed state), kidneys/collecting system (excretion), bladder (excretion), and bowel (variable). Liver shows moderate background uptake used as a reference. SUV >2.5 in a pulmonary nodule is considered suspicious for malignancy.

Reference: Grainger & Allison's Diagnostic Radiology, 7th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.