Computed Axial Tomography (CAT or CT)/
Ultrafact Computed Tomography (CT) Scan
Why
is the doctor performing this procedure?
To use sophisticated
x-ray technology to obtain clear and detailed three-dimensional images of
the heart and vascular system.
What
is the procedure?
Computed
tomography (CT or CAT Scan) is a very detailed x-ray that provides
information about internal tissues and organs in cross-sections (thin
slices). A computer takes the cross-section x-rays and uses them to
create three-dimensional images. The x-rays used in CT scanning are much
narrower than the x-rays used in standard x-rays, avoiding much of the
scatter inherent in routine x-rays. A CT scan of the heart can provide
detailed images of the following structures:
- Heart muscle
- Heart (coronary) arteries
- Lungs
- The aorta
- Pulmonary veins
- The sac surrounding the
heart (called the pericardium)
For a CT scan,
the patient changes into a hospital gown, and an intravenous line is
started so that contrast dye may be injected for enhanced visualization.
Sticky patches called electrodes, each with a wire, are attached to the
skin of the chest. Each wire is connected to an ECG machine to monitor
the heart's electrical activity throughout the procedure. The patient
lies down (with the arms above the head) on a moveable table that slides
into the CT machine. An x-ray tube (called the x-ray sensing unit)
rotates within the CT machine and around the body of the patient. The
table itself slowly moves the patient forward as images continue to be
taken. Then a computer analyzes and combines these x-rays to create
three-dimensional images with precise detail.
An
ultrafast CT provides images of the beating heart, and reveals calcium
deposits in the heart (coronary) arteries. The calcium deposits are
actually measured during an ultrafast CT, and reported as a coronary
artery calcium (CAC) score. The physician uses this score to determine
the amount of plaque (atherosclerosis) present within the coronary
arteries, and to predict the patient's risk of future coronary artery
disease and/or heart attack.
Where
is the procedure performed?
In the Imaging Department in the
hospital, or in some outpatient centers
including your physician’s office.
How
long does this procedure take?
A CT scan of the heart
or an ultrafast CT usually takes about 10-60 minutes.
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