MRI of the heart - Causes, symptoms and treatment. MF.

In recent decades, scientists have made considerable achievements in the field of diagnosis of diseases. However, despite the whole arsenal of available methods for examining patients, there are often complex and controversial cases when the diagnosis can not be denied or confirmed. Then the doctor can resort to highly informative methods of research, which include magnetic resonance imaging( MRI).On what is this method based?

In 1973, chemist Paul Lotberbur first published a scientific paper on the possibility of recording by means of computer systems the image obtained as a result of the "capture" of the energy released by the tomograph by hydrogen atoms( protons).In 1974, the American scientist RV Damadyan noted for the first time differences in the radiation of energy by protons of healthy and tumor tissues. In subsequent years, the method was improved. In Russia, the leading role in these achievements belongs to the scientist Ivanov VA

Magnetic resonance tomography is based on the ability of protons to release energy under the influence of strong electromagnetic radiation. In connection with the fact that the organs and tissues of the body are composed of molecules and atoms, the protons in cells and intercellular fluid also have such properties. This energy is captured and amplified by the receiver of radio frequency pulses, and then transferred to a data processing system where information processing and obtaining a layered image of human organs are performed using an analog-to-digital converter. Layered sections allow, with a difference of several millimeters, to visually assess the parts of an organ, which significantly improves the accuracy of the diagnosis. The natural contrast of body tissues is due to the different concentration of hydrogen atoms in them.

At present, along with the study of the brain and spinal cord, spine, joints of internal organs, a magnetic resonance examination of the heart and coronary vessels is applied. The general possibilities of the method are reduced to obtaining a high-precision layer-by-layer image of the internal structures of the heart, movement of valves and blood in the cavity of the heart and vessels. Also, MRI of the heart is performed with contrasting, when a contrast medium( more often gadolinium) enters the bloodstream entering the coronary arteries and the heart cavity, thus enhancing the "visibility" of the vessels. This method is called magnetic resonance angiography.

The advantages of the method are that it is not invasive( no penetration into the tissues), informative, safe, can be carried out repeatedly, does not carry radiation( since it does not use X-ray energy, unlike CT).
The shortcomings of the method can be attributed to the high cost of research. This is due to the fact that the clinic spends a lot of money not only for the purchase of equipment, but also for its maintenance, equipping the cabinet, payment for electricity, etc., when purchasing such a complicated technical device as a tomograph, etc.

Indications for MRIof the heart

MRI is prescribed in cases where the remaining methods of visualization of the heart( ultrasound of the heart) and vessels( angiography) do not allow you to clarify the diagnosis. It is prescribed for suspected cases not confirmed by other methods, such as:

1. Heart diseases
- heart tumors
- mediastinal tumors to determine the degree of tumor germination in heart tissue
- complex congenital heart diseases
- acquired heart defects
- complicated heart attackmyocardium - rupture of ventricular wall, rupture of ventricular aneurysm, formation of thrombi in the heart cavity
- cardiomyopathy, myocardial hypertrophy
- arrhythmogenic right ventricular dysplasia
- ishe(coronary angiography)( invasive method of investigation) is contraindicated by
- coronary artery anomalies and aneurysms, occlusion of aortic coronary shunts
- differential diagnosis of ischemia and myocardial infarction( assessment of myocardial viability and contractility)
- pericarditis - inflammatory lesions of the outer shell of the heart
- control of medical or surgical treatment of heart diseases, for example, withthe incision of an implanted occluder covering the defect of the interatrial and interventricular septa.

2. Diseases of the aorta and pulmonary artery
- congenital abnormalities of the structure of the vessels( coarctation of the aorta, defects in the valves of the aorta and pulmonary artery, open Botallov duct)
- exfoliating aortic aneurysm
- pulmonary embolism

Contraindications MRI of the heart

Despite the fact that carrying out a heart tomography is completely safe for the patient, the method has a number of limitations. Contraindications include:
- the presence of metal implants in the body - occluders, stents( it is recommended to carry out the examination not earlier than 1.5 to 2 months after the operation), intracardiac catheters and electrodes, skull clips, pacemakers and cardioverters - defibrillators, hearing aidsand implants in the cavity of the middle ear, kava filters. The impossibility of carrying out MRI with these constructions is explained by the fact that the metallic material not only can distort the image due to its magnetic properties, but it can still heat up and lead to the implant shifting with the loss of its functions. Exceptions are implants made of titanium, since it is not a ferromagnet. With artificial valve prostheses, the examination can be carried out, but the prosthesis can cause artifacts to appear on the image, thereby reducing informative value. In each case, the possibility of MRI is determined by the doctor individually, taking into account all indications and contraindications.
In addition, MRI is not recommended for such conditions as:

- 1st trimester of pregnancy
- psychiatric disorders( psychomotor agitation, panic attack)
- alcoholic or narcotic intoxication
- extremely difficult condition of the patient with the need to monitor and support vital functions(artificial lung ventilation, constant ECG monitoring)
- severe renal and hepatic insufficiency for MRI of the heart with contrast, since the contrast is excreted by the kidneys and can
- claustrophobia( in this case it should be investigated in an open-type tomograph, without being placed in a closed tomograph tunnel)

Preparation for a patient for MRI

Special preparation before the examination is not necessaryit takes. You can drink water and take small portions of food. Before entering the cabinet, you must remove all metal objects from the body( chains, earrings, other ornaments).If there are any implants in the body, the patient must necessarily notify the doctor about it.

How is MRI of the heart performed?

Survey can be conducted in a polyclinic or in a hospital. The patient before the study comes to the department of X-ray diagnostics, and he is invited to the study. The doctor conducts a conversation with him, then visually inspects the patient for the presence of scars after the operation for the implantation of metal devices. Next, the patient is offered to change into a comfortable shirt and lie down on the couch, which is connected to the tunnel of the tomograph. During the operation of the scanner, a sufficiently intense sound noise is created, due to the operation of the magnet and radio frequency coils. To reduce the unpleasant subjective sensations due to noise, the patient is offered to use headphones. The equipment is operated by a doctor using a remote from the adjacent cabinet, and in order for the patient to be able to notify the doctor about the increasing discomfort, the tomograph has a button that the patient can press. If a contrast agent is expected, the MRI of the heart is performed before and after contrasting. Contrast is injected intravenously after allergens. The whole study takes 20 to 50 minutes, sometimes more. After the end of the scanner's work, the patient is offered to leave the office, change into his clothes and wait for the result or escort him to the department where he is on treatment. At this time, the doctor evaluates the resulting series of images and issues an opinion.

Decoding of the results of the MRI of the heart

Tomogram of the heart and blood vessels

As a result of the examination, the doctor evaluates the anatomical structures of the heart and vessels, the volume of the chambers of the heart, movement of valves and blood in the chambers, the contractility of individual parts of the myocardium, the presence of damage zones or myocardial ischemia, scar or inflammatory processes incardiac tissue, the presence or absence of tumor lesions of the heart, the integrity of the septa and the walls of the atria and ventricles. Vascular contrast may reveal abnormalities in their structure, patency and extent of atherosclerosis or the absence of these features. Interpretation of the results can only be performed by a doctor radiologist, who has passed specialization in magnetic resonance imaging, any independent assessment of the conclusion by the patient is unacceptable. The patient must provide the received report to the doctor who prescribes the examination.

Complications of the

procedure Complications of MRI without cardiac contrast do not occur. With intravenous injection of contrast, nausea, vomiting, allergic reactions, Quincke's edema, anaphylactic shock may develop. Prevention is the careful collection of allergic anamnesis. To provide emergency assistance in such situations, the cabinet is equipped with anti-shock kit.

Doctor therapist Sazykina O.Yu.