Ultrafast Computed Tomography
A focused beam of electrons is used to generate x-rays of the heart. This relatively new imaging technique works so quickly that it captures images of the heart between beats, avoiding the distortion associated with conventional CT scanning, and can detect calcium deposits associated with atherosclerosis (the buildup of plaques) in the coronary arteries.
Purpose of the Electron-Beam CT Scan
- To detect coronary artery disease (CAD), especially in people who do not have symptoms but are at high risk
- To help determine whether lipid-lowering drugs are necessary in patients with a high cholesterol level but no other risk factors for heart disease
- To assess the effectiveness of treatment with lipid-lowering medications
- To help determine the cause of chest pain in emergency room patients with no history of CAD and normal initial test results
- To detect a mass or tumor in the heart
- To detect aortic aneurysm (weakness in the wall of the aorta, which is the main artery that carries oxygenated blood to the body from the heart)
- To examine heart tissue and evaluate heart damage after myocardial infarction (MI) or heart attack
- To evaluate coronary artery bypass graft openness (patency)
- To evaluate the outer sac surrounding the heart (pericardium)
- To examine the aortic arch (arch-like portion of the aorta) for suspected abnormalities
- To detect aortic dissection (tearing of the lining of the aorta)
Who Performs Electron-Beam CT Scan
- A radiologist or a qualified technician
Special Concerns about Electron-Beam CT Scan
- People who experience claustrophobia may have difficulty undergoing a CT scan, which takes place in a narrow, tunnel-like structure.
- This test may not be possible for severely overweight individuals (over 300 lbs).
- Pregnant women should not undergo this test because exposure to ionizing radiation may harm the fetus.
Before the Electron-Beam CT Scan
- Tell your doctor if you suffer from claustrophobia. He or she may prescribe a sedative that can help you tolerate the procedure.
- Avoid caffeine and do not smoke for 4 hours before the test.
- Remove any jewelry or other metallic objects that may interfere with clear x-ray images.
- Tell your doctor if you are pregnant or may be pregnant.
- Tell your doctor if you have a body piercing on your chest and/or abdomen.
What You Experience during Electron-Beam CT Scan
- You are asked to lie on your back with your arms above your head on a narrow examining table that slides into the center of the CT scanner.
- Remain as motionless as possible while the scanner takes multiple x-ray images of your heart. You will be asked to hold your breath during a portion of the scan.
- The procedure takes about 5 to 8 minutes.
Risks and Complications of Electron-Beam CT Scan
- There are no risks associated with the low levels of radiation from a CT scan.
After the Electron-Beam CT Scan
- Most patients can go home promptly after the scan.
- Sedated patients may be monitored for a short period until the effects of the sedative have worn off.
Results of Electron-Beam CT Scan
- A physician examines the scans for evidence of calcium deposits in the coronary arteries (seen as white specks on the x-rays). Detection of calcium indicates a high probability of CAD.
- If CAD is diagnosed, treatment will begin with diet, exercise, and/or medication.
- In some cases, additional tests, such as a cardiac stress test, may be required to establish a diagnosis and determine the extent of the problem.
The Johns Hopkins Consumer Guide to Medical Tests
Simeon Margolis, M.D., Ph.D., Medical Editor
Updated by Remedy Health Media