Chest CT Scan Health Article

Preparation

If IV contrast is to be used the patient should remain NPO (not given anything by mouth) for at least four hours. Occasionally to view possible esophageal pathology, patients will ingest oral contrast to help delineate possible mediastinal lymph nodes or gastric tumors. Patients should also remove any metal jewelry or clothing accessories to prevent artifacts from decreasing the diagnostic quality of the images. Certain lab values may be necessary before the scan is undertaken. These would include the BUN (blood uria nitrogen) and creatinine levels to asses the patients renal status. A high creatinine could contraindicate the use of IV contrast as the kidneys are the main organs which excrete the contrast. If a patient is on renal dialysis, then the values are usually higher, and the scan is prior to that day's dialysis treatment.

Aftercare

If the patient received IV contrast, a small bandage will be placed over the injection site, and it should be treated with the same care one would receive after donating blood. Patients should also drink plenty of clear fluids to help flush the iodinated contrast out of their kidneys to prevent any kidney damage.

If the patient is in renal failure then it will be necessary to dialyze the patient soon after the procedure. These arrangements should be made before hand with the knowledge and consent of the consulting nephrologist.

If the patient received any oral contrast it will pass through the GI tract with the next day or two. As the contrast used for CT is much thinner than the standard barium used for GI flouroscopy studies there should be no problems with constipation.

Complications

Several complications are possible, though are relatively unlikely as long as care is taken during the procedure. These precautions would include the careful super- vision of the injection of the IV contrast as an infiltration could result in a painful collection of contrast around the IV site. If the patient has a known allergy to iodine, then premedication will be necessary to prevent any sort of histamine reaction. The reaction can be mild, such as hives, to life-threatening if the patient were to have a larygospasm. With newer and safer non-ionic contrast, reactions have become less frequent, however this does not mean that technologists should be any less vigilant for signs of a mild reaction to the contrast media. There is also a small risk of renal failure in certain high-risk patients.

Results

The results are given in a written report that is sent to multiple locations including the patients referring physician, the file room of the radiology department and to the patients permanent medical record if they were an inpatient at the time of their study. A verbal report will occasionally be used as well to help speed up the communication of results to the appropriate physicians. If there are previous examinations, the radiologist will consider if there has been a change ad judeged by the appearance of any pathology on the images.

Health care team roles

The main team member involved in the CT of the chest is the radiologic technologist who has been trained to perform CT exams. If the physician ordering the procedure can confirm the lab values before the patient arrives, and if they are an inpatient, assuring that the patient's IV line is patent and safe for use will streamline the examination.

KEY TERMS

Computed tomography—The technique of imaging a patient with ionizing radiation to diagnose disease process.

Non-ionic intravenous contrast—A injectable xray dye that mixes with the blood to enhance structures aiding their ability to be judged as health or diseased.

BOOKS

American College of Radiology. Manual on Contrast Media. 4th Edition.

Horton, K. M., and E. K. Fishman "Spiral CT of the Esophagus and Stomach." In Spiral CT: Principles, Techniques and Applications. E. K. Fishman and R. B. Jeffery, eds. New York, NY: Lippincott-Raven Press 1998; pp.221–230

J. Paul Dow, Jr.