Final answer:
A small bowel follow-through is considered complete when the contrast material has passed through the entire small intestine and reaches the large intestine.
Step-by-step explanation:
The small bowel follow-through is considered to be complete when the contrast material has passed through the entire small intestine and reaches the large intestine. This can be observed on X-ray images taken at different time intervals after the patient drinks a contrast solution. The progression of the contrast material helps to evaluate the structure and function of the small intestine.
For example, in the case of incomplete small bowel follow-through, if the contrast material does not reach the large intestine within a certain timeframe, it may indicate an obstruction or problem in the small bowel.