FIGURE 1. (B) PET image (emission image, CT-corrected for attenuation) showed intense tracer activity in posterior stomach region. (A) CT showed very dense contrast (CTHU >3,000) in same area as result of high-grade partial gastric outlet obstruction. Patient had ingested barium several days before. (C) Nonattenuation-corrected image did not show this "gastric tracer uptake." Uptake in stomach was artifactual from inaccurate attenuation correction in presence of very dense barium. Nonattenuation-corrected images can help resolve such a case. (Reprinted with permission from [13]).