Pattern of benign and malignant uptake within the abdomen and pelvis on FDG positron emission tomography-computed tomography

Learning Objectives 1. Review the fundamentals, pathophysiology, and FDG PET-CT imaging findings of various abdominopelvic PET-avid lesions and correlation with other imaging modalities including MRI. 2. Review pearls and pitfalls of FDG PET-CT imaging.

FDG PET-CT is one of the key imaging techniques in body imaging to evaluate oncologic processes. Due to the overall increase in worldwide incidence of cancer, role of FDG PET-CT is ever expanding. The unique combination of structural and functional information obtained from FDG PET-CT allows for a variety of application including (1) initial evaluation of a neoplasm and the extent of malignant disease which assist in cancer staging, (2) assess treatment response and (3)evaluate for tumor recurrence. FDG PET-CT like other diagnostic modalities is not 100% specific as there are a fair number of benign (physiologic and inflammatory) entities that appear FDG PET-avid and may be misinterpreted as neoplastic. Benign uptake of FDG has been reported in over 25% of cases with most common cause of benign uptake reported has been inflammation whether infectious or noninfectious. Increased uptake is likely from increased WBC recruitment which carry GLUT 3 and lesser extent GLUT 1 receptors. The specificity of these findings can be improved by anatomic uptake localization and characterization on CT. In this exhibit, we will review fundamentals (physics and physiology) of FDG PET and PET/CT imaging, review common clinical uses of PET-CT and case-based discussion of clinical features, pathophysiology, histology features, imaging findings ( CT, PET-CT and/or MRI) highlighting radiological pearls, treatments and prognosis of various neoplastic and benign conditions including: appendicitis, diverticulitis, Biguanides, esophagitis, barret’s esophagus, colitis, messenteric fat necrosis, UTI, pyelonephritis, obtructive uropathy, bladder diverticula, atherosclerosis, endograft etc.