Before my abdominal ct scan the technician gave me a big glass of water and said i shld drink and finish it up..what is that for?thanks?

Contrast - best view: Most likely the liquid was oral contrast. This improves the sensitivity of the ct scan in identifying abnormalities. Specifically, the contrast stays in the intestine and is not absorbed so it provides a nice outline of the entire gastrointestinal tract. This helps the physician to visualize gastrointestinal motility, assess for blockages and look for some scarring. Sometimes, masses can be seen.

Contrast: Likely it is a liquid that is a material that highlights the inside of the intestines on ct scan, allowing the radiologist to see the internal structures and differentiate the internal abdominal structures better. Can be called oral contrast material.

Water is a contrast: We often use water to fill up the stomach to help see its walls or interior. The water acts like a contrast as it is lower density than most tissues. Oral contrast is usually iodine or barium based and is a positive contrast agent (higher density than tissue).

Water as contrast: Ct uses contrast both positive and negative to assess mucosa of bowel. Positive contrast usually contains iodine or barium to be seen on ct. Negative contrast can use water to see mucosa. One glass of water would show the stomach well. For the small bowel multiple glasses of water have to be ingested beginiing hours before the ct, called ct enterography.