NM Pet Report: Abdomen/Pelvis: Persistence of hypermetabolic activity with in rectum, SUV 4.5, compared to prior SUV 5.6. What could its meaning?

Several reasons. Standard uptake value (SUV) GREATER than 2.5 is increased but this is to be correlated with GI evaluations, including presence of polyps, inflammatory dis, diverticulitis or even malignancy. The PCD may need to check if you need Biopsies, if not already done, in the areas where increased sugar uptake seen by PET scan is noted, and one explanation could be resolving inflammation given the decrease.