Magnetic resonance imaging (MRI) of the chest organs
Magnetic resonance imaging of the chest organs is a method of imaging using a powerful magnet and radio waves, with the help of which an image of the chest organs (blood vessels, heart, lungs) is subsequently built. During an MRI of the chest organs, the patient does not receive radiation exposure (radiation exposure).
Performing the procedure of magnetic resonance imaging of the chest organs
When carrying out an MRI of the chest organs, the patient must wear clothes that do not contain metal (fasteners, belts, buttons). If there are metal implants in the patient's body (clips for aneurysms, joint prostheses, plates and screws for osteosynthesis, pacemakers and neurostimulators), MRI is also not possible and not safe, because the resulting image will be blurred and there is a risk of displacement (migration) of the implants in the body.
Recently, medical device manufacturers have begun to produce the above-mentioned components implanted into the patient's body using special alloys that are not affected by the magnetic field of the MRI machine. The manufacturer indicates such compatibility of the device with the MRI procedure in the documentation attached to it.
The patient is placed on the sliding table of the MRI machine, which then automatically moves with it to the center of the scanner to start the study.
Some types of MRI of the chest organs require the use of a special drug - contrast. The contrast agent is administered to the patient through a vein in the elbow or hand. The contrast in MRI of the chest organs, accumulating in the altered tissues, enhances the resulting image. This gives the most detailed picture of the state of the organ or tissue being examined for the radiologist, who will describe the images obtained by MRI.
Intravenous Gadolinium Contrast is a non-ionic paramagnetic contrast agent for magnetic resonance imaging. Paramagnetic properties determine the contrast enhancement during MRI. Intravenous administration of the drug (contrast) causes an increase in the signal from the tissue sites of only those organs that have dysfunction as a result of damage in any pathological process. This provides more informational content of the obtained images in comparison with the MRI data of the same organ without the use of contrast enhancement.
The radiologist and his assistant are in a separate room during the chest MRI procedure, observing through the glass the operation of the device and the patient's condition. The duration of the MRI examination takes from 30 to 60 minutes, depending on the volume of the planned examination of the chest organs of the patient.
Patient preparing for a chest magnetic resonance imaging procedure
Before the scheduled examination, the patient is asked not to eat or drink fluids 4-6 hours before the start of the chest MRI procedure.
It is necessary to clarify in advance whether the patient sent by the doctor for an MRI examination has a fear of a closed space (claustrophobia). In such a case, he will need to first take a sedative, which will cause slight drowsiness and relieve anxiety. There is also an "open" type of MRI machine ("open MRI", "MRI with an open-loop"), which has free spaces on the sides, which does not frighten the patient.
The MRI machine (magnetic resonance imaging) installed in the radiology department has a large space with an aperture of 70 cm, which leads to a decrease in the number of patients who need preliminary sedation during chest examinations.
Our patients are invited to undergo an MRI scan using a device with a magnetic field of 3.0 T (Tesla). It is also possible to conduct MRI with intravenous contrast (Omniscan contrast) to increase the visual difference between healthy tissue and tumor. Weight restriction (for a patient with a large weight) during magnetic resonance imaging - up to 200 kg.
Before performing an MRI procedure of the chest organs, the patient should be excluded:
- the presence of clips for aneurysm of the arteries of the brain
- the presence of intravascular stents
- the presence of artificial metal heart valves
- cardiac defibrillators and pacemakers
- neurostimulators of the brain and spinal cord
- cochlear implants in the inner ear
- kidney disease, dialysis (risk of toxic effects from intravenous contrast)
- the presence of artificial joints
- the presence of metal fragments in the body after accidents, explosions, injuries, etc.
The MRI device installed in the department of radiation diagnostics has a strong magnetic field - 3 Tesla, therefore, the room where the device is installed should be avoided from:
- fountain pens, pocket knives, metal-rimmed glasses
- metal jewelry, watches, bank credit cards, and passes, hearing aids
- metal hairpins, safety pins, clasps, and zippers
- removable dentures (removed before the tomography).
Tolerability of the procedure of magnetic resonance imaging of the chest organs by patients
The MRI procedure itself does not cause any physical pain or discomfort in the patient. In the case when the patient cannot lie still in the MRI machine (children) or is nervous, a short-acting sedative drug can be used to help him calm down and relax during the procedure. The movements of the patient's body during the MRI of the chest organs will lubricate the images received by the apparatus, introducing errors in the diagnosis.
The surface of the MRI scanner table may be too cool and hard for some patients, so they can be covered during the scan with a blanket or a pillow under their head (if this does not interfere with the main examination).
An intercom built into the MRI machine allows the patient to communicate during the diagnostic procedure with the medical staff located in the next room. Some MRI tomographs also have built-in video monitors and headphones, which allows the patient to be distracted while he is in the tomograph during the scanning process.
After the completion of the chest MRI procedure, the patient can continue their normal life. He will not have any restriction in diet, physical activity, except for those cases when during the MRI scan he was sedated.
Indications for magnetic resonance imaging of the chest
MRI of the chest allows specialists to obtain an image of the patient's organs located there (heart, bronchi, lungs, etc.) to assess their functional state or identify organic changes that have occurred in them.
MRI of the chest organs is performed in patients in the following cases:
- as an alternative to CT angiography to avoid radiation exposure to the patient's body
- to clarify the already available data obtained during previous radiography or computed tomography
- diagnostics of pathological growth of tissues of some organs of the chest (heart, aorta, vein, lungs)
- assessment of the state of blood flow (aorta, vein, heart, lungs)
- assessment of the condition of the lymph nodes and blood vessels in the chest cavity
- assessment of the chest organs in three-dimensional reconstruction from different angles
- detecting the stage of cancer - the spread of a tumor from the chest organs to other parts of the body (metastases)
- determination of the stage of development of cancer of the chest organs allows you to choose an adequate method of treatment and make a prognosis in the future condition of a patient with oncology.
In the case of the norm, the examined person on MRI of the chest organs will not reveal any pathological changes.
Detected changes on magnetic resonance imaging of the chest
An MRI of the chest can show the following abnormalities in the heart, lungs, or chest:
- developmental anomaly and acquired pathology of the vessels of the lungs (arteries, veins)
- developmental anomaly and acquired pathology of the lymph nodes of the chest
- dissection of the walls of the aorta
- stenosis (narrowing) of the aorta
- myxoma (tumor) of the atrium
- defect in the atrial septum
- developmental anomaly and acquired pathology of the bronchi
- cardiac tamponade (blood or pericardial effusion)
- chronic obstructive pulmonary disease, chronic obstructive pulmonary disease (COPD, COPD)
- corticalization (narrowing of the lumen) of the aorta
- constrictive pericarditis ("armored heart")
- cystic lung damage
- tumors of the esophagus
- ischemic cardiomyopathy
- lung tumor (lung cancer)
- mitral regurgitation (acute and chronic)
- mitral valve prolapse
- pathological masses and tumors in the chest cavity
- pericardial effusion (fluid in the pericardial cavity)
- pericarditis (inflammation of the bursa)
- pathological changes in the pleura - thickening of its petals with pleurisy and effusion in the pleural cavity
- pulmonary edema
- restrictive cardiomyopathy
- obstruction (blockage of the lumen) of the superior vena cava
- aneurysm of the thoracic aorta
- thymoma or tumor of the thymus (cancer of the thymus gland)
- tumors of the sternum.
The obtained data of the results of MRI of the chest organs are further analyzed by the attending physician of the patient, who develops a plan for the necessary additional examination and treatment.
Potential risks and complications of chest magnetic resonance imaging
The MRI machine does not use X-rays in its work, unlike CT tomographs. Until now, there have not been any references and reports in studies from doctors about the possible side effects of an MRI tomograph on the body as a result of its use.
Most types of contrast or contrast media contain gadolinium. Intravenous contrast is safe for chest MRI. Allergic reactions to an MRI drug administered through a vein are extremely rare in patients. But gadolinium can be harmful to patients with impaired kidney function, through which it is excreted from the body, or in patients on dialysis to cleanse the blood plasma. If the patient has renal insufficiency, caution should be exercised in prescribing such studies of the chest organs on an MRI machine with contrast enhancement.
The strong magnetic field generated by the MRI machine can damage the operation of a pacemaker or other type of electronic implant in the patient's body. Also exposed to the magnetic field are metal fragments and plates in the body, which can move and shift.
At this stage in the development of medical technology, MRI is not the most valuable tool for detecting or monitoring minor changes in lung tissue, because the lungs contain air and this makes visualization difficult. Examining the chest organs on an MRI machine may not be beneficial for several reasons:
- high research cost
- a long duration of the scanning process
- high sensitivity to the movement of internal organs and the whole-body during tomography.