Pharmacologic interventions in PET/CT imaging: Indications and imaging protocols

Learning Objectives 1. Discuss the indications and adverse effects of pharmacologic interventions in PET CT imaging. 2. Recognize various metabolic processes or physiologic changes induced by drugs. 3. Describe the imaging protocols in drug- augmented PET CT imaging.

PET CT imaging is valuable in assessing pathophysiology in a variety of organ systems. Pharmacologic interventions are often used in PET/CT imaging to modify or monitor physiologic changes, thereby optimizing the image to facilitate the diagnosis. Insulin, ativan and metoprolol have been used for oncologic PET/CT studies in order to overcome false- negative or false- positive results of hyperglycemia, claustrophobia, brown fat uptake, and muscular uptake. Pharmacologic intervention with diamox is used for brain reserve studies. Pharmacologic interventions performed during PET/CT imaging for urinary malignancies include diuretic administration such as furosemide. Recombinant thyrotropin can be used in patients with previously treated thyroid carcinoma who require PET/CT follow-up scanning for recurrent thyroid disease. Cardiac pharmacologic stress agents are commonly performed with regadenoson and it would be important to know how the vasodilatory effects of regadenososn may effect the intepretation of cardiac PET CT images. The goal of this presentation is to discuss indications and adverse effects of pharmacologic interventions in PET/CT imaging used to avoid false-negative or false positive results. Recognition of variuos metabolic processes and different physiologic changes induced by drugs are important in understanding how they would affect image data and image quality. It is recommended to have defined protocols in place in order to use drug- augmented PET CT imaging and avoid non diagnostic or poor diagnostic quality scans due to altered biodistribution or physiologic state. In this presentation, we review the indications, mechanism of action, and adverse effects of these drugs and present imaging protocols and examples of their use in PET CT imaging.

Research Support Alena Kreychman, M.D. J. Antonio Obando, MD*,† * Department of Radiology Yale New Haven Hospital, New Haven, CT. †Division of Nuclear Medicine Veterans Administration CT Healthcare System, West Haven, CT