Which upper GI position is optimal for demonstrating the pylorus and duodenal bulb?

The choice of a 45-degree right anterior oblique (RAO) position is optimal for visualizing the pylorus and duodenal bulb during an upper gastrointestinal (GI) study. In this position, the stomach is rotated along its long axis, allowing for better separation and visualization of the pylorus and duodenal bulb, as well as the duodenum. This angle facilitates the natural anatomical distinctions between these structures, often preventing overlap with adjacent organs.

In the RAO position at 45 degrees, gravity aids in moving the contents of the stomach downwards, providing a clearer view of the duodenal bulb, which is located directly near the pyloric region. This view allows radiologists to assess any potential abnormalities more effectively.

Other positions, such as a 90-degree left posterior oblique (LPO) or a 60-degree right anterior oblique (RAO), do not provide the same degree of detail as they may result in inadequate visualization of the key areas of interest due to overlapping structures or their orientation. The 30-degree right posterior oblique (RPO) is also less effective because it does not achieve the necessary rotation to distinctly demonstrate the pylorus and duodenal bulb as effectively as the 45-degree