Pitfalls in PET/CT oncologic imaging: A series of interesting cases

Learning Objectives Understanding common pitfalls is important for the radiologist evaluating cancer patients. We present 7 cases that demonstrate interesting examples of pitfalls in PET/CT imaging of patients undergoing oncologic evaluation. Knowledge of these interesting cases of pitfalls in PET/CT imaging will aid in avoiding mistakes when interpreting these often complex images.

PET/CT has become an integral part of oncologic imaging for screening certain populations of patients, staging cancers and evaluating response to treatment or recurrence. Many pitfalls and artifacts in PET/CT imaging have been described. Pitfalls in PET/CT imaging can be due to iatrogenic causes, inflammatory processes, benign tumors, other variants and secondary malignancies. Knowledge of common pitfalls is important for the radiologists evaluating cancer patients. We present 7 interesting cases that demonstrate these categories. These cases show abnormal 18F-FDG uptake in cancer patients undergoing evaluation for response to treatment and screening for recurrent disease. Cases presented include: Patient with treated colorectal metastases to the liver found to have, not recurrent disease, but a new high grade endocrine tumor causing increased activity in the liver. Patients with thrombus and central venous catheters causing abnormal increased activity on PET/CT. Patients with diskitis/osteomyelitis and abscess, adrenal adenoma, grey matter heterotopia, and elastofibromas, all of which show increased activity on PET/CT. Knowledge of these interesting cases of pitfalls in PET/CT imaging will aid in avoiding mistakes when interpreting these often complex images