CT angiography is a special imaging examination method that is used to visualize blood vessels within the human body.
Below you will find further information and selected specialists for CT angiography.
Computed tomography is an important imaging procedurein medicine. Doctors often abbreviate this examination technique to "CT" or "CT scan". It is an examination using X-rays that shows the tissue (bones, organs, vessels) in layers.
A CT scan is used, for example, in serious traffic accidents (polytrauma). This allows doctors to quickly and reliably detect or rule out injuries to bones, internal organs or even bleeding. CT is also the imaging procedure of choice for a more precise examination of tumor diseases.
CT angiography is a CT examination with a special focus on the blood vessel system. However, as blood is no different from normal tissue fluid, it is necessary to administer a contrast agent.
CT angiography makes it possible to visualize the differences in density that exist between different tissues. Water, for example, has a different density to bone or air.
In order to visualize the blood vessels even better, the patient is also given a contrast agent, as in conventional angiography. These are iodine-containing and radiopaque liquids that are not permeable to X-rays.
Doctors administer the contrast agent via a vein in the arm shortly before the CT scan. This allows the contrast agent to spread through the vessels with the blood flow. These can then be precisely visualized and examined. For example, when it comes to constrictions, occlusions or bleeding.
In CT angiography (CTA), the patient lies back on the couch while the device moves through the circular opening @ Dirk Rothe /AdobeStock
Another variant is MR angiography, in which magnetic resonance imaging (MRI) is used.
CT angiography can take targeted images of the blood vessels in different parts of the body.
These include above all
Typical diseases and conditions for which CT angiography is used are, for example
Doctors examine narrowed carotid arteries more closely to find out whether an operation is necessary to prevent a stroke. If the degree of narrowing is > 70%, surgery is usually recommended
If a stroke has already occurred, CT angiography can show whether and where there are clots in the brain
This involves imaging the arteries in the legs, in particular constrictions and occlusions. Depending on the findings, further treatment may be recommended (e.g. balloon dilatation or bypass)
Modern multi-line computed tomography is used as part of the examination. Blood vessels such as arteries and veins can be segmented using fast-working computers and displayed in 3D images that rotate freely. While the raw images are always black and white, modern images can be colored.
One of the advantages of CT angiography is that there is no need to penetrate the patient's body. There is no direct puncture, as is the case with classic angiography. The examination techniques are the same for all vascular regions so that the patient does not notice any differences.
In MR angiography (magnetic resonance imaging), the patient lies in a long tube. CT is a large ring-shaped device that surrounds the patient. The CT examination is therefore much faster and is also suitable for patients who are known to be claustrophobic.
CT angiography is particularly suitable for patients who have a pacemaker. Magnetic resonance imaging is not possible for them. It also benefits very restless patients, for whom a long magnetic resonance imaging scan would also be unfavorable.
The 3D representation of the coronary arteries using CTA @ samunella /AdobeStock
CT angiography is usually performed on an outpatient basis. The same rules apply as for other examinations with iodine-containing contrast media. It is important here that known allergies to contrast media are reported.
It is then usually necessary to administer certain medication to prevent an allergic reaction (shortness of breath, nausea, reddening of the skin, shock). These are cortisone and anti-histamine agents (antihistamines), which the patient receives shortly before the examination. Prior to the CT angiography, doctors examine the patient's kidney function by taking blood samples and carrying out a laboratory analysis.
In total, CT angiography takes no more than ten minutes. For the examination, the patient lies on their back on a couch.
Modern CT devices work using the multislice method. This means that they produce several slice images at the same time. Newer devices also use so-called low-dose technology. This requires only 50 percent of the radiation to produce accurate images.
During the examination, the patient must hold their breath at certain intervals as instructed by the medical staff.
At the end of the examination, the patient should drink plenty of fluids in order to excrete the contrast medium quickly . In addition, in the case of diabetes mellitus or renal insufficiency, a deterioration in kidney function is possible.
In summary, CT angiography is an examination technique that is now available in almost all clinics for all vascular diseases. From constrictions and occlusions to bleeding.
The administration of an iodine-containing contrast agent makes it possible to visualize the vessels in any region of the body. However, patients with a known contrast agent allergy should take medication to prevent allergic reactions.
The examination only takes a few minutes and can also be carried out if the patient is claustrophobic. Afterwards, the patient should drink plenty of fluids to eliminate the contrast medium and protect the kidneys.
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