Angiography

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Digital subtraction angiography of the head
CT angiography of the hands
Sinus vein angiography on MRI
Venography in deep vein thrombosis

Angiography or -graphy is called in medicine, the 1923/1924 introduced radiological representation of vessels , usually blood vessels by means of diagnostic imaging techniques such as X-ray or magnetic resonance imaging (MRI). For this purpose, a contrast agent is often injected into the blood vessel . The interior of the vascular filled with the contrast agent is then shown on the image of the recorded body region. The resulting image is called an angiogram . With MRI, angiographies without contrast media are also possible, which saves the invasive puncture of the vessel. However, not all questions can be answered satisfactorily with MRI angiography.

Procedures and names

Depending on the underlying imaging method, a distinction is made between various angiographies:

In addition to arterial ( arteriography ) and venous ( venography ) blood vessels, lymphatic vessels ( lymphography ) and non-anatomical vessels such as vascular prostheses or dialysis shunts can also be displayed. The representation of the coronary arteries is called coronary angiography , the angiography of a varicose vein after direct puncture is called varicography .

The short form Angio for angiography is common in the medical field.

Indications

Angiographies are mainly used to diagnose important vascular diseases .

Furthermore, angiography is occasionally required in order to have clarity about the course of important blood vessels when planning an operation .

Digital subtraction angiography

Investigation process

First, a catheter or an injection needle is introduced into the vascular system and then positioned in or in front of the exit of the blood vessel of interest. Before administering the contrast agent, a normal image ( blank exposure ) can be made of the examined body region. If the contrast medium is then injected into the vessel via a catheter or needle, recordings are made of it in quick succession. If these images are to be saved in digital form, the empty image can be subtracted from the angiography images . Disturbing image elements that are present in both images (e.g. bones) are masked out, which makes it easier to evaluate the recordings ( digital subtraction angiography ).

Depending on which vessel was punctured, special post-treatment (e.g. a pressure bandage ) is necessary.

Risks and benefits

The risks arise, on the one hand, from puncturing the blood vessels, especially when arteries are punctured. Hematoma , after bleeding , aneurysms and fistulas can result. The use of a catheter and guide wire can also injure blood vessels away from the puncture site. The formation of thrombi on the materials introduced into the vessel (e.g. on the guide wire) can lead to embolisms with the consequence of vascular occlusion. Secondly, the administration of the contrast agent can cause allergic reactions, damage the kidneys ( Kontrastmittelnephropathie ) or - in case of a pre-existing hyperthyroidism (sneigung) - to an acute hyperthyroidism lead (hyperthyroidism). In the case of x-ray imaging, it is important to note that radiation exposure is not low, especially in the case of longer interventions .

Angiography shows the contrast between the examined vessels and the blood flow and thus offers the combination of morphological information about the filling image and functional information about the inflow and outflow behavior of the contrast as an expression of the hemodynamics . The greatest and unique advantage of angiography is that interventions in the vessel can also be carried out during the examination. Narrowed vessels can be distended ( angioplasty ), blood clots can be dissolved and aneurysms can be eliminated. Also shifted to catheter be re-aligned correctly.

Angiocardiography

In angiocardiography , the interior of the heart ( atria, chambers ) can be displayed in order to assess size and function. Furthermore, large vessels, possibly existing shunts and also the coronary vessels that supply the heart can be shown precisely.

Access is either venous (right heart catheter) or via an artery (left heart catheter). The left heart catheter is inserted either via the femoral artery in the groin or the brachial artery in the elbow, which is advanced into the left ventricle or the exit of the coronary arteries (coronary angiography). The right heart catheter is inserted through the femoral vein in the groin or the brachial vein in the elbow. After the catheter has been inserted, a contrast medium is injected, the distribution of which can then be recorded with a cinematographic film.

For some questions, tissue samples can also be taken at the same time or current impulses can be emitted in order to check the conduction system. In addition, therapeutic interventions can be made, especially in the coronary arteries (e.g. balloon dilatation , stent installation).

Contraindications for catheterization are allergies to the contrast agent, hyperthyroidism , decompensated heart failure and coagulation disorders.

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Web links

Wiktionary: Angiography  - explanations of meanings, word origins, synonyms, translations

Individual evidence

  1. ↑ Axel Karenberg : Neuroradiology. In: Werner E. Gerabek , Bernhard D. Haage, Gundolf Keil , Wolfgang Wegner (eds.): Enzyklopädie Medizingeschichte. De Gruyter, Berlin / New York 2005, ISBN 3-11-015714-4 , p. 1046.