What Happens During A CT or CAT Scan?
The CT scanner is a large donut-shaped machine that takes X-rays at different angles around the body. A CT technologist will explain the procedure to the patient and have the patient lie down on a narrow table. The CT technologist will move to a room adjacent to the exam area where s/he can observe the patient, supervise the exam and monitor the images on the screen.
The table will glide through the scanner’s “donut hole,” while the technologist, via intercom, instructs the patient to lie very still, and on occasion, hold his/her breath as the X-rays are taken. The “donut ring” will rotate around the patient, taking X-rays from all angles. Often a clicking or buzzing sound is heard as the table moves and the cylinder turns. The digital X-rays are processed on a computer to produce high resolution image “slices” of the body, which are visualized on the computer monitor.
Some CT exams require a contrast material to highlight areas of the body. Depending upon the area being scanned, the contrast may be given orally, intravenously, or a combination of methods. The actual CT scan takes only minutes, but, depending upon the area being scanned, exam times are from 15 to 30 minutes.
Preparing For a CT or CAT Scan
Patients are asked to notify their healthcare provider if they are pregnant; have asthma or allergies to medications, contrast dye, or iodine; or have certain medical conditions such as diabetes, asthma, heart disease, kidney problems or thyroid conditions.
Patients are generally asked to not eat or drink anything but water for at least four hours prior to the exam. If CT oral contrast is ordered, drink it according to the directions and time provided for the specific CT exam.
Once at PIC, patients will change into a gown. A locker is available to secure clothing and personal items. The technologist will review the procedure and if needed, provide the patient with additional CT oral contrast to drink. If intravenous contrast is needed, it will be administered at the start of the exam. Patients may experience a warm sensation throughout the body after the contrast injection and a metallic taste in the mouth. These sensations typically disappear in a few minutes.
Occasionally a patient may be allergic to the contrast material. Reactions may include sneezing, hives or difficulty breathing. Anyone having a reaction will be treated prior to his or her release.
After the procedure, drink plenty of fluids for several hours to assist in flushing out the contrast material. Normal activity and diet can be resumed.
CT or CAT Scan Results
Images from the CT exam are reviewed and interpreted by a PIC radiologist, who will dictate a report, which is transcribed and sent to the healthcare provider who ordered the exam. This is usually accomplished within 3 days after the exam. Patients should contact their healthcare provider for the results of their CT exam.
Abdominal CT or CAT Scan
Because CT imaging is a non-invasive procedure that shows detailed, cross-sectional views of all types of tissue, it is becoming the preferred method for visualizing and diagnosing diseases of the liver, spleen, pancreas, kidneys, bladder, bowel and colon.
Abdominal CT scans are used to monitor tumors and other conditions of the abdomen before and after treatment, and to detect, diagnose and treat vascular disorders that may lead to stroke, gangrene or kidney failure. The CT’s acute detail and accuracy may eliminate the need for invasive exploratory surgery and surgical biopsy. Please note, CT accuracy may be compromised due to metallic objects in the abdomen, such as surgical clips, barium in the intestines from a recent barium study; and stool and/or gas in the bowel. Please advise the CT technologist if you have clips or have had a recent barium study.
Preparing for an Abdominal CT Scan
Do not eat or drink anything except waterfour (4) hours prior to examination. Thirty minutes before exam, drink one bottle of oral CT contrast. This contrast is available at our Front Desk, or often is given to you by your healthcare provider when the exam is scheduled.
Preparing for an Abdominal/Pelvic CT Scan
If the exam is scheduled before 11 a.m., patients should drink one bottle of oral CT contrast at 9 p.m. the night before the exam. Eat and drink as usual after taking the oral contrast until midnight. Do not eat anything after midnight until 30 minutes prior to the exam, when the second bottle of oral CT contrast will be consumed.
If the exam is scheduled after 11 a.m., drink one bottle of oral CT contrast four (4) hours prior to the exam time. Do not eat anything after the first bottle of oral CT contrast. Thirty minutes prior to the exam, drink a second bottle of oral CT contrast.
If intravenous contrast is needed, it will be administered at the start of the exam. Patients may experience a warm sensation throughout the body after the contrast injection and a metallic taste in the mouth. These sensations typically disappear in a few minutes. If rectal contrast is needed, a small tube will be placed in the rectum and contrast will be infused into the bowel, similar to an enema, at the start of the exam.
Pulmonary CT or CAT Scan
A CT scan shows detailed images of any part of the body, including bones, muscles, fat and organs.
CT scans of the chest provide more detailed information about organs and structures inside the chest than standard x-rays, making it an excellent tool for assessing the chest and its organs for tumors and other lesions, injuries, intra-thoracic bleeding, infections, unexplained chest pain, obstructions or other conditions. It may also be used to evaluate the effects of treatment on thoracic tumors.
Patients are asked to notify the CT technologist if they have metal objects within the chest, such as a pacemaker or surgical clips or have had a recent barium study as these may interfere with the accuracy of a CT scan of the chest.
If no contrast medium is required, patients may stay on their regular diet.