Computed tomography (CT)

Schuylkill Medical Imaging

Computed tomography (CT) combines the use of X-rays with the latest computer technology to take detailed images of any body part. Using a series of X-ray beams, the CT scanner creates cross-sectional images. A computer then reconstructs the "slices" to produce the actual pictures. Considering that some slices are as thin as half a centimeter, a CT scan offers much more image detail than a traditional X-ray, which means your doctor obtains detailed images to help make the most accurate diagnosis.

What Should You Expect During a CT Scan?
During the scan, the patient will be asked to rest motionless on a padded table for 5 to 15 minutes depending on the area of the body to be scanned. The table moves every few seconds as the images are obtained. The patient will hear faint humming and clicking sounds. Once the images are taken, a radiologist will review the images to ensure all of the area has been covered. Sometimes because of breathing or motion inside the body additional images are needed. Additional images do not mean there is a problem.
Preparations & Considerations
For the intravenous contrast studies, do not eat 4 hours prior to the exam. You should wear loose, comfortable clothing, avoiding garments that have zippers, belts, or buttons made of metal. You may be asked to wear a gown during the procedure. You will be asked to remove keys and jewelry from the area being scanned.

If you have a history of claustrophobia, an allergy to iodinated contrast, asthma, or a strong allergic history, please notify our office when scheduling the examination. Premedication may be necessary depending on the clinical history. If premedication is indicated, the radiologist or referring physician can call your pharmacy. Upon arrival at the office, please notify the front desk staff and the technologist that you have an allergic history, or have been premedicated.

Women should always inform their physicians and the technologist if there is any possibility of pregnancy.

Frequently Asked Questions

What are Contrast Agents?
Contrast agents are used to image tissues and structures that are not normally seen, or not seen very well. Intravenous contrast agents are used to enhance organs and visualize blood vessels. Oral contrast agents are used to visualize the digestive tract.
How do CT scans differ from MRI scans?
CT and MRI images sometimes look very similar, but the equipment used to perform the scans is different. CT uses ionizing radiation just as with a routine X-ray, while MRI uses a magnetic field. Depending on the clinical indications, one may be preferred over the other, or both may be desirable. CT scanners are faster and as a result, claustrophobia and movement are not as problematic as with the MRI scanner.
Who performs the CT scan?
Medical radiation technologists specially trained in the operation of CT scanners perform the procedure. The technologist also administers oral and intravenous contrast.
What will I feel during the scan?
CT scanning causes no pain, just as a routine X-ray is painless. If intravenous contrast is used, you may feel warm and flush and get a metallic taste in your mouth. These sensations normally disappear after a few minutes.
How long will the scan take?
The time required will depend upon the type of scan. If oral contrast is required, about 45 to 60 minutes is needed for the contrast to move through your digestive tract. Actual scan times vary from a few seconds to several minutes. If no oral contrast is required, the examination will take about 15 to 30 minutes, including the time for intravenous preparation and interview. In some cases additional scanning is required as scans are tailored to suit individual diagnostic needs.
Will I need to drink anything?
Most abdominal scans require the patient to drink a barium sulfate oral contrast mixture. This mixture is flavored and not at all unpleasant. Oral contrast highlights the stomach and upper intestine providing the radiologist with a detailed image for review. If you are scheduled for a CT scan requiring oral contrast, you will be asked to arrive one hour before the scan time.
Can my spouse/friend stay in the room with me?
No. CT scanners use ionizing radiation and only the patient requiring the scan is permitted in the room.
Why does the technologist leave the room?
The technologist must operate the computer system to complete the scanning procedure.
Should I have a CT scan if I am pregnant?
No. If you are pregnant or suspect that you may be, you should not have a CT scan or any type of X-ray examination. You should inform the technologist if you suspect you may be pregnant. Alternative arrangements may be made to meet your medical needs.
Why do some patients need X-ray dye and others not?
Depending upon your condition and the images required to diagnose or rule out pathology, X-ray dye or intravenous contrast may or may not be needed. The radiologist reviews the information sent to us by your physician and decides what contrast is needed to provide the best images.
Are there any instructions I need to follow after the scan?
If no contrast was used, there are no instructions and you may continue with your normal activities. If intravenous contrast or oral contrast is used, you will be instructed to drink water for the rest of the day to help eliminate the contrast.
Will I have to hold my breath?
Depending upon the body part being scanned, you may be required to hold your breath several times during the scan. It is important that you not move during the scan. The technologist will instruct you on breathing prior to the start of the scan.
Can I breastfeed after an injection of intravenous contrast?
You should not breastfeed for 48 hours after an injection of intravenous contrast.
Does the radiation stay in my body?
No. CT uses a thin beam of radiation that is captured by detectors as it exits your body.