AJR:195, July 2010
Carmel G. Cronin, Priyanka Prakash, Michael A. Blake
Educational Objectives and Key Points
1. IV contrast-enhanced FDG PET/CT has been found to be superior to contrast-enhanced CT alone and to unenhanced FDG PET/CT.
2. Use of IV contrast material increases lesion conspicuity, which is of particular importance in the evaluation of lesions that do not always accumulate FDG.
3. The CT component of PET/CT can be tailored to include diagnostic-quality unenhanced, arterial phase, and delayed imaging as needed to characterize a particular lesion.
4. Use of low-density oral contrast agents can aid in the evaluation of gastrointestinal FDG uptake because distending the bowel can reduce FDG uptake and simultaneously facilitate confident exclusion or diagnosis of luminal and mural disease.
5. High attenuation values associated with the presence of high-density IV contrast material in vascular structures or of concentrated barium can cause attenuation-correction artifacts during attenuation correction for PET/CT. The benefits of the use of oral and IV contrast media for diagnostic CT are well established. The combination of FDG PET and contrast-enhanced CT has been found to be superior to contrast-enhanced CT alone and to unenhanced FDG PET/CT for precise definition of disease in patients with abdominal and pelvic malignant diseases [1, 2]. Pitfalls exist, however, when certain contrast agents cause attenuation-correction anomalies that simulate or mask pathologic changes. We describe and illustrate the use of oral and IV contrast agents for PET/CT and show how to take advantage of their benefits and recognize and avoid their pitfalls.