Imaging method in which arterial structures are evaluated three-dimensionally with multi-slice CT during intravenous administration of an iodine-based contrast agent.
Indication
- Evaluation of stenosis and plaques in suspected coronary artery disease (coronary CT angiography)
- Peripheral artery disease: lower extremity vascular mapping in cases of leg pain, coldness, and non-healing wounds
- Screening of carotid and cerebral artery stenosis and aneurysms
- Evaluation of large vessel diseases such as aortic aneurysm, aortic dissection, and aortitis
- Diagnosis of pulmonary embolism (clot in the pulmonary arteries)
- Renal artery stenosis, mesenteric artery ischemia, and pre-transplant vascular evaluation
- Detection of vascular injuries and active bleeding sources after trauma
Preparation
- Fasting for 4-6 hours before the procedure is recommended; medications can be taken with a small amount of water
- Kidney function tests (creatinine/eGFR) are evaluated in advance
- Metformin-containing medications are paused before the procedure in advanced renal insufficiency and resumed 48 hours later per physician instructions
- Beta-blockers may be given to slow heart rate in coronary CT angiography; sublingual nitrate may be given to dilate the coronary arteries when needed
- History of previous iodine contrast reactions, asthma, and kidney disease must be reported
- Metal objects that need to be removed during the procedure (jewelry, bra wires) are taken off in advance
How it's performed
- The patient is placed supine on the CT table; a wide-bore IV line (usually in the antecubital area) is established
- ECG electrodes are placed; in coronary CT, images are synchronized with the cardiac rhythm
- Iodine-based contrast is injected at high speed via an automatic injector, immediately followed by multi-slice CT scanning
- Breath-hold instructions of 5-15 seconds are given during the scan; remaining still is important
- The acquired data is converted into a three-dimensional vascular map using specialized computer software
- Total procedure time is 15-30 minutes including preparation; active scanning lasts only a few seconds
Post-procedure
- After the procedure, the patient is observed for 15-30 minutes, and the IV line is then removed
- Generous fluid intake is recommended (to accelerate contrast elimination)
- Patients receiving beta-blockers for coronary CT are observed for low blood pressure and slow heart rate
- Metformin is restarted in patients after kidney function is confirmed
- The report is shared with the clinical team; for findings requiring treatment, catheter angiography, stenting, or surgical planning is arranged
Risks
- Allergic reactions to iodine-based contrast; usually mild but rarely severe anaphylaxis may develop
- Contrast nephropathy; risk increases especially in older patients, those with diabetes, and those with existing renal insufficiency
- Rare but serious lactic acidosis risk due to interaction with metformin use, especially in patients with low eGFR
- Standard CT angiography involves ionizing radiation; dose varies depending on the protocol used, with dose-reduction techniques applied in modern devices
- Beta-blockers used in coronary CT may cause low blood pressure and slow heart rhythm (bradycardia)
- Contrast extravasation is a very rare complication that may require intervention
FAQ
When is classical (catheter) angiography needed instead of CT angiography?
CT angiography is a non-invasive screening method; catheter angiography is used when stenosis needs to be confirmed, balloon-stent application is required, or treatment planning is needed.
Why is the heart rate lowered in coronary CT angiography?
For clear visualization of the coronary arteries, the heart rate generally needs to be below 65 beats per minute. Beta-blockers are given when needed for this reason.
My kidneys are functioning at the borderline; can CT angiography be performed?
In mild to moderate renal impairment, the contrast dose is limited and risk is reduced through hydration. In advanced renal insufficiency, alternative methods (MR angiography, ultrasound) are evaluated as the first option.
Is the procedure painful?
No. Only a slight needle prick is felt when the IV line is placed. When contrast is given, a widespread warmth in the body and a metallic taste in the mouth may occur, but these resolve quickly.
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