An abdominal CT is a good way to more extensively look for a blockage or obstruction. Typically, it is performed with contrast for best results, but can be done without if necessary.
Usually patients are advised to not eat within 4-6 hours before the test. Often patients are required to drink oral contrast immediately before the procedure in order to improve images and accentuate any potential problems. This may involve the need for arrival at the radiology center about an hour in advance in order to allow time to drink the barium and coat the intestines. Sometimes physicians do not require this, particularly if the patient is symptomatic or has a hard time eating or drinking.
Before the test:
In addition to oral contrast, the patient may be given an IV for IV contrast. Allergic reactions to IV dye are not uncommon and include shortness of breath, rashes, etc. Often premedication with benadryl is necessary to prevent a reaction. Normal feelings from the contrast include flushing, sensation of heat, and desire to empty the bladder. These pass within a few seconds.
During the test:
The patient is instructed to lie very still on a table on his/her back, usually with his/her arms and hands resting above the head. The table is advanced so that it enters a tube (scanner), but not closed like an MRI. He/she is instructed to hold his/her breath for a few seconds at a time as images are taken as the scanner circulates around the body. Several images are taken, depending on the number of organs being tested.
After the test:
If there are no emergent complications, the patient is allowed to resume normal activity. If oral contrast was used, he/she may experience white stool for a few days, diarrhea, constipation, and a feeling of fullness.
Positive results may indicate a small bowel obstruction or blockage, tumor, infection, or a number of other illnesses. Typically, results are available rather quickly after the procedure on a preliminary basis.