From this article you will learn: what is MRA( magnetic resonance angiography) than it differs from other similar studies. The algorithm of the procedure when it is assigned, and what it can show.
Contents of the article:
- Indications for MR angiography, as shown in the study
- Preparation of
- How is the study of
- Contraindications
- Possible complications of
With the help of magnetic resonance angiography, vascular pathologies are diagnosed, a magnetic resonance tomograph is used during the procedure. Under the influence of the radio-frequency pulse and the magnetic field of the device, the magnetic field of hydrogen atoms in liquids, in this case in the blood, changes, since it has a different chemical structure in comparison with immobile tissues( bone, muscle).These short-term energy changes are fixed in the form of images.
An example of a magnetic resonance angiogram 
A modern magnetic resonance tomograph with the help of which it is possible to obtain images of magnetic resonance angiography The device registers information on the velocity of blood in vessels. In areas where there is an uncommon narrowing or widening, the blood flow velocity slows down or accelerates, indicating the location of the pathology.
Thus, due to different types of MR angiography( phase-contrast, time-of-flight, 4D), two-dimensional or three-dimensional images of the blood circulating over them are obtained not by the blood vessels themselves.
This is one of the most informative methods of diagnosing vascular pathologies, which allows to isolate venous and arterial blood flow, assess its speed and accurately determine the presence and localization:
- Stenosis( narrowing).
- Occlusion( obstruction of the lumen).
- Aneurysms( expansion, risk of rupture).
- Atherosclerosis( cholesterol plaques).
- Vasculitis( inflammation).
- Bundles of the vascular walls.
Unlike classical angiography, a catheter is not inserted into the vascular bed for magnetic resonance angiography, no radioactive contrast agents and X-rays are used, so it is considered to be the safest. Sometimes, in order to get a sharper image, substances containing gadolinium( a special chemical element) can be used, this is justified by its pronounced magnetic properties.
More often MR angiography is assigned for the diagnosis of vascular pathologies and circulatory disorders of the brain, heart, neck, less often for the evaluation of the vascular bed of other parts of the body( liver, kidneys, limbs). To date, this is the only way to assess the status of the vascular bed in real time.
An angio-surgeon, phlebologist, neurosurgeon or neurologist may prescribe the procedure, but it is performed by an angiographic doctor, a radiologist or a radiologist.
Indications for the procedure
Indications for the procedure are:
- ischemic or hemorrhagic stroke;
- ischemia, dyscirculatory encephalopathy and dystonia( impaired blood supply) of cerebral vessels;
- sclerosis( fragility) of blood vessels against the background of endocrine diseases( diabetes mellitus);
- bruises, cysts, brain tumors;
- a thrombosis of vessels of a brain, a backbone;
- congenital or acquired abnormalities of vascular development and position;
- craniocerebral and other trauma;
- stenosis of the renal arteries;
- hearing, vision, speech, headaches, sudden and frequent loss of consciousness, tinnitus;
- behavior disorders and difficulties in performing household skills for no apparent reason;
- muscle weakness, tingling and numbness of the limbs;
- epileptic seizures, impaired coordination of movements.
MR angiography is prescribed to deliver or clarify the diagnosis, assess the patient's condition after treatment or surgery on the vessels of the heart, brain, neck, less often other parts of the body.
With discirculatory encephalopathy, hypoxia occurs in some parts of the brain. MRA allows you to identify these areas of What will show the angiography of
Magnetic resonance angiography is indispensable for the diagnosis of functional changes in the vascular bed:
- of congenital heart defects;
- stenosis( narrowing of the lumen) and thrombosis of blood vessels;
- aneurysms( dilatation of the walls) of the aorta and aneurysmal dissection;
- atherosclerotic formations;
- vasculitis( inflammation of the walls of blood vessels).
In the process of research, the specialist receives an absolutely reliable and detailed image of the vessels: normal arteries and veins have an even and clear contour, without loops and sharp bends, thickening along the course of diminishing the lumen( vascular "branches").
Thus, in dealing with pathology, a specialist can accurately establish any, even the smallest anomaly and the cause of the violation of blood supply to the body. For example, as a result of MRA, ischemia is diagnosed as a result of traumatic brain injury or stroke, disseminated sclerotic changes in the cerebral vessels, various hematomas, cysts, tumors, etc.
Preparation for the
procedure Before the appointment of the procedure, the patient is handed a questionnaire that he mustfill in, indicating the presence of implants, prostheses, pacemaker, intrauterine device and other foreign objects in the body. Some of them are an absolute contraindication for carrying out MRA, the other part can distort the readings of the device.
Be sure to inform the attending physician about the presence of an allergic reaction to medications and fear of being in a confined space.
There are no other stages of preparation: fasting or taking regular medications is not required.
How the
is Undergoing The MRI device for magnetic resonance angiography is a horizontal tube in the form of a tube into which the patient is placed lying on a special pull-out table.
The walls of the device are equipped with a powerful magnet and equipment, with their help the device generates a magnetic field and radio frequencies and fixes the result of the survey, transmitting signals to the main computer installed in the adjacent room.
The procedure can take from 30 to 90 minutes, usually the study is carried out in several stages( from 2 to 6), each of which sends a series of readings to the main computer.
During the procedure, it is absolutely necessary to lie absolutely still, and this is one of the main difficulties for the patient.
The rest of the method is painless, sometimes a tingling sensation or heat from radio waves or electromagnetic impulse is felt on the skin:
- Before the procedure, it is necessary to get rid of metal objects( earrings, watches, rings).Iron parts should not be on clothes - they can distort the magnetic field during the study.
- Clothes - free, not constraining movements and not interfering with lying.
- The patient is placed on the diagnostic table, the limbs and head are fixed with straps.
- If necessary, enter a contrast agent to the patient put a dropper, piercing the vein on one of the hands.
- The table is pushed inside the device, the patient can hear the start of the operation of the coils of radio-frequency pulses( characteristic snapping, tapping).
- After the work is completed, the table is pulled out from the apparatus.
The procedure is performed on an outpatient basis, so the recovery period is not needed. The exception is the case where a sedative is required: most tomographs in our country are closed devices, without any windows on the sides, the patient is in the dark. In the presence of mental abnormalities or nervous disorders, this can trigger a panic attack, so MRA is produced under anesthesia.
There is a doctor sitting at the computer who is doing the research( angiographic, radiologist, radiologist).Decoding and interpretation of the results takes from 10 to 30 minutes, the conclusion is given to the patient's hands immediately after the procedure. Conclusions, purpose and recommendations on the results of the study are made by a specialist who directed MR angiography.
Contraindications
| It is absolutely contraindicated to do the procedure in the presence of | Relatively contraindicated in the presence of | Is contraindicated in the presence of |
|---|---|---|
| Pacemakers | Insulin pumps | |
| Middle ear implants( electronic or metal) | Heart valve prostheses | |
| Metal implants | Nonmetallic and non-electronic middle ear implants | |
| Large fragments in the body | Heart failure instages of decompensation( exacerbation) | |
| Clips, which are installed in the channel of a large cerebral vessel, so thatprevent the bleeding | Nervous stimulants | |
| Clips that are placed in the channel of other blood vessels other than the brain | ||
| Pregnancy | ||
| Extreme claustrophobia( fear of confinement) and other mental abnormalities that can prevent it from lying still |
With relative contraindications, the health risk and the reasonableness of the procedureevaluates the attending physician.
Possible complications resulting from the procedure
The examination procedure is absolutely painless and does not cause the patient any inconvenience, except for involuntary immobile lying in the dark for a long time.
No side effects and complications;Even with substances containing gadolinium, the risk of developing an allergic reaction is minimal. Therefore, magnetic resonance angiography is the only method that can be prescribed to patients with an allergy to contrasting iodine preparations.
Due to the absence of radiologic load, the diagnosis can be repeated without harm to health.
Before injecting a contrast agent into the vein, a salt solution is sometimes injected, which can cause a reaction in patients on dialysis or with kidney failure. Therefore, those sent to the survey are pre-filled with a special questionnaire or questionnaire, where all concomitant diseases are introduced.
During the procedure of MRA:
- , the effect of magnetic field and radio frequencies can cause the patient to have different sensations - heat, tingling, which quickly and without a trace pass;
- in easily excitable or nervous patients may appear discomfort from the sounds of the device, so before starting the study the doctor suggests using earplugs;
- in patients with severe claustrophobia or other mental disorders, enclosed space and darkness can cause uncontrolled panic attacks. In this case, use sedatives, a mild general anesthesia;
- patients with a body weight of more than 100 kilograms may simply not fit in the device, since it is designed for certain loads.
After the procedure, there may be a slight discomfort, caused by prolonged lying in a stationary position. Restorative period is required only for those patients who underwent magnetic resonance angiography under general anesthesia.
