Ke Wang BA, Abstract Co-Author: Nothing to Disclose

Matthew R. Palmer PhD, Presenter: Nothing to Disclose

Awais Ahmed MBBS, Abstract Co-Author: Nothing to Disclose

Alan Moss MD, Abstract Co-Author: Nothing to Disclose

Gerald Mordecai Kolodny MD, Abstract Co-Author: Institutional license agreement, E-Z-EM, Inc Royalties, E-Z-EM, Inc

The mechanism and cellular localization of physiologic FDG uptake in the gastrointestinal tract remain unknown. We hypothesized that concomitant medications taken preceding PET/CT would influence intestinal FDG uptake.

281 successive PET/CT scans demonstrating physiologic GI uptake were identified in a retrospective review. SUVmax of the uptake along the GI tract was measured for each scan. Medication records were examined with regards to current and past usage of antibiotics, insulin, proton-pump inhibitors (PPI), oral hypoglycemic agents (OHA) and beta-blockers. Only scans performed within the medication prescription period were included for analysis, and compared to patients not taking these medications. Statistical analysis was performed using Student’s t (unpaired, two-sided).

Patients with antibiotic usage within 4 weeks of the PET/CT scan had significantly lower GI FDG uptake compared to controls (average SUVmax 5.37± 2.55 vs. 7.69 ± 2.81, p=0.00003). Higher GI FDG uptake was noted in patients taking OHA (average SUVmax 10.32 ± 4.42 vs. 6.69 ± 2.39, p=0.0003) and PPIs (average SUVmax 7.83 ± 3.00 vs. 6.46 ± 1.88, p=0.0005) compared to controls. No difference in GI FDG uptake was seen in patients with beta-blocker (average SUVmax 6.87± 2.37 vs. 6.91 ± 2.64, p=0.92) and insulin usage (average SUVmax 6.64 ± 2.66 vs. 6.84 ± 2.44, p=0.76).

Gastrointestinal FDG uptake is affected by use of proton-pump inhibitors, oral hypoglycemic agents and antibiotics. The reduced intestinal FDG uptake noted with antibiotics may occur due to impaired uptake by colonic bacteria. The increased intestinal uptake in patients taking OHAs may reflect a higher blood-lumen glucose gradient.

Use of antibiotics prior to PET/CT scans can potentially minimize physiologic intestinal FDG uptake and improve the diagnostic utility of PET/CT in GI disorders.

Wang, K, Palmer, M, Ahmed, A, Moss, A, Kolodny, G, Effects of Medication Usage on Physiologic FDG Uptake in the Gastrointestinal Tract on PET/CT.  Radiological Society of North America 2010 Scientific Assembly and Annual Meeting, November 28 - December 3, 2010 ,Chicago IL. http://archive.rsna.org/2010/9009101.html