Understanding the technology
About This Technology.
CT Scan 512 Slices is an X-ray scanner that combines hundreds of thin slices into three-dimensional images of the heart and blood vessels. Doctors use it to look for narrowing and calcium in the coronary arteries, to assess the aorta and leg arteries, and to plan procedures such as transcatheter aortic valve implantation.
What Is CT Scan 512 Slices?
A CT (computed tomography) scan uses X-rays and a computer to create cross-sectional images of the body. You lie on a table that moves slowly through the ring of the scanner. The number 512 refers to how many thin image slices the scanner can produce in one rotation. The computer then assembles these slices into three-dimensional images of the heart and blood vessels.
Because the heart keeps beating, the scan is synchronized with an electrical recording of your heart (ECG), so images are taken when the heart is relatively still between two beats.
Common Types of Examination
- Coronary calcium score. A short scan without contrast that measures calcium deposits in the walls of the coronary arteries, one sign that plaque is present.
- Coronary CT angiography. A contrast agent is given through an IV line in your arm so the inside of the coronary arteries can be seen, including narrowing and plaque.
- CT of the aorta and peripheral arteries. Assesses widening (aneurysm), tears (dissection), or narrowing in the aorta and the arteries of the legs.
- Procedure planning. The aortic valve, the aorta, and the access arteries are measured before transcatheter aortic valve implantation (TAVI) or aortic stent graft placement.
Preparation and the Scan Itself
Before the scan, the staff will ask about allergies, kidney disease, the medicines you take, and whether you might be pregnant. For a scan with contrast, you are usually asked to fast for a few hours, and an IV line is placed. If your heart rate is fast, your doctor may give you medicine to slow it so the images are not blurred.
During the scan, you lie on your back and are asked to hold your breath for a few seconds. When the contrast goes in, you may feel warm for a moment. The scan itself is short; most of the time is spent on preparation. Afterward, you can eat, drink, and return to your usual activities unless your doctor advises otherwise.
Limitations and Risks
A CT scan uses X-ray radiation. The dose is adjusted to the examination protocol, but it is still a consideration, especially during pregnancy. The contrast agent can cause allergic reactions and calls for caution if your kidney function is reduced. Heavy calcium or an irregular heart rhythm can make narrowing difficult to assess. CT also shows the shape of the arteries, not how much blood flow to the heart muscle is reduced. Your doctor may therefore need other tests, such as a treadmill test, stress echocardiography, or cardiac catheterization.
Reading the Results and Your Doctor's Role
Your doctor decides whether a CT scan is needed, which type of examination is appropriate, and whether another test would be more suitable. The images are interpreted by a radiologist together with a cardiologist, and the results are explained to you during your consultation.
Clinical use
Uses and Benefits.
Whether this technology suits your condition is decided by a doctor after an evaluation.
- Looking for narrowing and plaque in the coronary arteries (coronary CT angiography)
- Measuring the coronary calcium score to help assess the risk of coronary artery disease
- Evaluating chest pain in selected patients whom the doctor considers to be at low to intermediate risk
- Examining the aorta for widening (aneurysm) or a tear (dissection)
- Assessing narrowing in the leg arteries and other peripheral arteries
- Measuring the aortic valve and access arteries before TAVI
- Planning aortic stent graft placement and other structural procedures
- Examining abnormalities in the shape of the heart and great vessels, including congenital heart disease
Benefits for the Doctor's Assessment
Seeing the Coronary Arteries Without a Catheter
With contrast given through an IV line in your arm, the inside of the coronary arteries can be assessed without passing a catheter into the blood vessels of the heart.
Many Slices in One Rotation
The scanner can produce up to 512 thin slices in one rotation. This wide coverage helps record the heart within a short time while you hold your breath.
Calcium Scoring Without Contrast
Calcium deposits in the coronary arteries are measured with a short scan without contrast. The SCCT consensus uses this score to help assess risk in selected people who do not yet have symptoms.
Detailed Measurements for Procedure Planning
Three-dimensional images are used to measure the aortic valve, the aorta, and the access arteries before TAVI or stent graft placement, in line with the SCCT consensus on CT for TAVI.
Brief Technical Information
- Type of examination
- Computed tomography (CT) of the heart and blood vessels
- Number of slices
- Up to 512 image slices in one rotation
- Image source
- X-rays (ionizing radiation)
- Contrast agent
- Iodine-based contrast through an IV line for CT angiography; not used for calcium scoring
- Sedation
- Not required
- Service location
- Cardiovascular Diagnostic Center
