Study protocol was changed.

Study 1: A randomized, crossover trial using elemental or semi-solid diets containing contrast medium as a tracer given to bedridden PEG patients. The distribution of the administered diets is assessed at the distal esophagus, proximal and distal stomach using a plain CT before and 1 hour after the administration.

Study 2: A randomized, crossover trial using elemental or semi-solid diets containing 13C sodium acetate as a tracer given to bedridden PEG patients. 13C breath tests are performed to estimate gastric emptying.

Study 1: A mix of elemental or semi-solid diet (300 kcal/300 mL ) and contrast medium (5ml) is administered using PEG, respectively. Using a plain CT, the distribution of the administered diet is assessed at the distal esophagus, proximal and distal stomach before and 1 hour after the administration. The volume of the residual diet at the distal esophagus, proximal and distal stomach is compared between an elemental and semi-solid diet.

Study 2: Either the elemental diet or semi-solid diet (200 kcal/200 mL) is labeled with 100 mg [13C]sodium acetate (Cambridge Isotope Laboratories Inc, Cambridge, MA) and is administered in the first 15 min of the examination at the same speed using the PEG.

Inclusion Criteria:

• Bedridden PEG patients are admitted for fever which is the most common reason for admission of PEG patients to our hospital.

Exclusion Criteria:

• Regular use of gastric acid blockers, motility drugs, benzodiazepines or opioids, any clinical evidence of acute infection, a history of abdominal surgery, and an American Society of Anesthesiologists physical status of class IV or V.