The Radiologic Procedure

1. The patient is placed in the prone position for overhead radiographs.
   
   
   • In this position, the center of the abdomen is compressed, making the entire abdomen more uniform in thickness, thus permitting more uniform x-ray penetration through the small bowel.
     
     
   • Another advantage to the prone position is that there is better separation and less overlapping of small bowel loops.
     
     
   • Additionally, loops of ileum tend to migrate cephalad and become less compacted in the pelvis when the patient is lying on his/her abdomen.
     
     
2. In the interval between overhead radiographs, the patient is generally allowed to walk about or sit in a dressing booth outside the x-ray room.
   
   
   • A debilitated patient can be left on the x-ray table between radiographs or can be moved to a stretcher outside the room if it is needed for other examinations.
     
     
   • The patient who is unable to sit or stand should be placed in the right-side-down position to encourage gastric emptying-and then rolled periodically from one side to the other to better distribute the barium and speed its transit by using the assistance of gravity.
     
     
3. Overhead radiographs are made on 14 x 17 inch (35 x 43 cm) format.
   
   
   • The interval between exposures depends on the speed of barium transit through the small bowel. Routinely, we obtain films at 15-minute intervals for the first hour and at 30-minute intervals thereafter.
     
     
4. Each overhead radiograph should be carefully examined as soon as it is processed. Any suspected abnormality should be evaluated with fluoroscopy and compression spot images.
   
   
   • Many authorities recommend, even in the absence of abnormalities on the overhead films, that periodic fluoroscopic inspections and compression spot imaging be performed.
     
     
   • In any case, after the barium has reached the right side of the colon, compression spot images of the terminal ileum are routinely obtained. The terminal ileum is the most common location of small bowel pathology. Representative compression spot images of small bowel in all four quadrants of the abdomen are obtained to demonstrate that the entire small bowel was evaluated fluoroscopically.