Residual drugs in the stomach? A case report.

BACKGROUND: High-density material identified in the stomach on computed tomography (CT) most commonly represents ingested drugs, oral contrast agents, or blood. Distinguishing between these is critical, as misidentifying drugs or contrast as active gastric bleeding may lead to unnecessary interventions. We report a rare cause of hyperdense gastric material on CT, other than the three etiologies mentioned above. CASE PRESENTATION: A 25-year-old man with Crohn's disease presented to the gastroenterology department with suspected disease recurrence. At 11:20, a gastroscopy identified an antral ulcer, bile reflux, and a duodenal stricture, through which the gastroscope (approximately 10 mm in width) was able to pass. A subsequent CT enterography performed at 13:49 revealed several round, high-density lesions within the stomach on non-contrast and contrast CT images, which appeared distinct from the surrounding gastric mucosa. While retained oral medication was initially suspected, the patient confirmed he had ingested nothing other than a 2.5% mannitol solution, taken for CT enterography preparation following the gastroscopy. To investigate the composition of these lesions, we combined artificial gastric juice, artificial bile, and 2.5% mannitol in a test tube. This combination yielded a visible precipitate. We therefore conclude that the round lesions observed on CT most likely represent this precipitated material. CONCLUSION: This case highlights a fourth etiology of high-density gastric material on CT; it is important for radiologists and clinicians to be aware of this situation to prevent misinterpretation of images.