​Children's Heart Center

CT Scan

In conventional X-rays, specific detail about internal organs and other structures is not available. When greater detail is needed, patients might require a computerized tomography scan, also called a CT or CAT scan. During a CT scan, an X-ray beam moves in a circle around the body. This allows for many detailed views of the same organ or structure. The X-ray information is then interpreted by a computer, which displays it in two-dimensional form on a monitor.

CT scans may be done with or without contrast dye, a substance taken by mouth or injected into an IV line that causes the particular organ or tissue being studied to be seen more clearly.

When contrast dye, sedation or anesthesia is required, the patient will need to fast prior to the procedure. Patients will be provided detailed instructions from the physician or another health care professional.

It is important to let the CT staff know in advance if the patient has ever had a reaction to contrast dye, or if he or she is allergic to iodine or seafood. Likewise, the staff should be notified if a female patient is pregnant or could be pregnant.

Performing a CT Scan

  • The CT scanner is located in a large room. The patient will lie on a narrow table that slides into the hollow tube-shaped scanner. If a contrast angiography study is requested by the doctor, the patient will have an IV line for contrast dye to be injected during the exam.
  • Parents are often able to stay with the patient in the CT scan room until the exam is ready to begin, at which time, they are usually asked to wait in another area during the exam to avoid exposure to unnecessary radiation.
  • The imaging team members performing the exam are positioned in a special control room adjacent to where the scanner and patient are located. The imaging team can see patients through a large window and monitor them continuously during the procedure. If the patient is not sedated, speakers are located inside the scanner so the patient can hear instructions from the control room and so the imaging team can hear and respond to the patient.
  • Once the procedure begins, the patient will need to remain very still at all times so that movement will not adversely affect the quality of the images. At intervals, the patient will be instructed to hold his or her breath, if possible, for a few seconds. He or she will then be told when to resume normal breathing. Young children who cannot hold still for the procedure will be given medication to help them relax or sleep during the exam.
  • If the CT scanning protocol requires imaging with and without contrast, the patient will receive contrast medication through an IV about halfway through the exam. He or she may feel warm or flushed just after the dye goes into the vessel. This feeling usually passes quickly.
  • When the procedure is finished, the table will slide out of the scanner. If the patient receives medication for relaxation or sleep, he or she will be monitored until the medication wears off and he or she is awake again. If an IV was inserted, it will be taken out after the exam is over and the patient is awake.
  • Patients may be asked to wait for a short time while the radiologist reviews the scans to make sure they are clear and complete. If the scans are not sufficient to obtain adequate information, additional scanning may be done. The average time required to perform the exam ranges from 30-60 minutes.

Use of Sedation and Anesthesia for CT Scans

Many patients have feelings of anxiety about being in the tunnel of the scanner. Although this anxiety often goes away, sedatives can be used to help patients relax, if necessary. This requires the expertise of doctors and nurses with advanced training in pediatric anesthesiology and sedation.

Patients who can’t lie still, including adults with special needs, may need general anesthesia so they can be completely asleep during the scan. Anesthesia is administered through a breathing mask or an IV. The anesthesiologist will maintain the patient’s breathing during the scan with a breathing tube. When anesthesia is required, one of our board-certified pediatric anesthesiologists will perform and monitor the sedation. When the exam is completed, the breathing tube will be removed and the patient will recover in a special-care area.

With sedation or anesthesia, the patient may feel groggy, tired or sleepy for a period of several hours after the exam. However, these effects will usually disappear within a day or so.