Angio of the carotid arteries
Magnetic resonance angiography of the carotid arteries is a safe and extremely accurate test that, when performed in time, can reduce the risk of stroke.
Here, a health-safe strong magnetic field and radio waves are used to image anatomical structures. These interact with hydrogen ions present in water molecules. Since water is one of the components of the blood that flows through the arteries, the use of contrast is no longer necessary. Even if it is administered to further map the course of the vessels, this is done through a venflon inserted at the beginning of the examination. Moreover, the so-called gadolinium-based contrast agents are much better tolerated by the body than the iodine-based ones used in CT scans.
All this means that angio-MR of the carotid arteries can be repeated as needed at virtually any frequency. Also in pregnant women – at the same time, although no negative effects of the magnetic field on the developing baby in the womb have been found, MRI is avoided during the first trimester of pregnancy as a precaution.
Blood supplying, among other things, the eyes, ears or tongue and, above all, the brain with oxygen and nutrients, flows to the head through the carotid arteries. A narrowing or blockage of these arteries can therefore cause the aforementioned organs to stop functioning properly.
The human body has developed some mechanisms to protect the brain from ischemia, but this has a major drawback:
- Progressive disease of the carotid arteries may therefore only become apparent when more than 70% of their lumen is closed.
Fortunately, the condition of the vessels can be assessed by at least several means, the most noteworthy of which is magnetic resonance angiography, also known as MR angiography (abbreviated as angio-MR) or carotid artery angio-MRI.
Indications for magnetic resonance angiography of the carotid arteries.
Successive narrowing of the carotid arteries can produce no obvious symptoms. The first is often only a cerebral ischemic stroke – transient (lasting up to 24 hours) or resulting in irreversible neurological changes, severe disability or death due to the death of brain cells that have run out of glucose or oxygen.
It happens that when these components are supplied in insufficient amounts for a long time, signs of deteriorated brain function can be observed, such as:
- Paroxysmal headaches and dizziness, fainting,
- imbalances,
- Paresis, paralysis and consequent muscle weakness or atrophy,
- Sensory, visual disturbances,
- impaired concentration and memory, and even consciousness,
- Speech or speech comprehension disorders.
The aforementioned signs of ischemia are perfectly visible in an MRI head scan.
Narrowing and stiffening of the carotid arteries can also make a person tire faster and blood pressure rise.
Angiography of the carotid arteries can visualize not only stenosis of the carotid arteries, but also other anomalies in their structure, malformations, inflammation or the presence of clots or aneurysms. In addition, one can:
- Evaluate the blood supply and vascularization of cancerous tumors in the neck area;
- qualify the patient for surgical treatment – especially when this cannot be done based on ultrasound alone;
- choose the optimal method of invasive arterial dilatation – percutaneous stent placement or surgical intervention;
- Assess the sequelae of cerebral ischemia – detecting foci of stroke.
Increasingly, imaging tests are being performed not only when abnormalities in the carotid arteries are suspected, but also prophylactically, especially in people with ischemic heart disease.
This would presumably make it possible not only to expand them in time, but even to detect the problem early enough for conservative treatment, consisting of anticoagulants and lifestyle changes – and ultimately reduce the number of deaths from stroke.
Contraindications to carotid artery angiography by magnetic resonance imaging.
Most often, owners of permanently located objects in the body, such as:
- pacemaker,
- insulin pump,
- cochlear implant,
- neurostimulator,
- Endoprostheses, stabilizers, screws, implants or orthopedic plates – which are made of ferromagnetic materials. However, various types of implants/prostheses are currently being used, which are easily approved for MRI.
- Metal filings (especially in the eye), shot, bullet fragments.
Electronic devices in a strong magnetic field could malfunction, and metal components could heat up and move, leading to damage to surrounding tissues.
Preparation for carotid artery agio study:
You should bring with you the results of all imaging studies that have been performed to date that relate to the area being examined.
One should wear clothes that are free of metal elements, such as zippers, snaps, buckles, hooks or bra whalebones, and even sequins and metallic prints. This is because they could change their position under the influence of the magnetic field, disturbing the image obtained.
The same goes for metal pollen present in some cosmetics: hairspray, illuminating lotions or makeup products. It’s best to steer clear of them.
Course of carotid artery angio study:
Angio-MR of the arteries does not hurt and takes up to several tens of minutes. Medical personnel supervise the examination, staying in a separate room during the test, but remaining in contact with the person being examined through an intercom, which is a system of speakers and microphones, as well as visually through glass and a camera.