Magnetic Resonance Imaging: What it is and what it can detect

by 4D Medical | Oct 31, 2024 | Medical equipment, Medical techniques

The magnetic resonance imagingalso known by its acronym IRM, is a non-invasive diagnostic imaging technique which produces three-dimensional anatomical images. The MRI uses powerful magnets and radiofrequency waves which allow the creation of detailed images of the organs, tissues and internal structures of the body. Unlike other methods such as radiography or computed axial tomography (CT), magnetic resonance imaging (MRI) can be used to create detailed images of organs, tissues and structures inside the body. does not use ionizing radiation or X-raysIt is a safe, painless medical test that does not cause any harm to the patient.

This is one of the most widely used techniques for the production of medical diagnostics, analyze the different tissues and check for any disease, injury or abnormality.. MRI is used by health professionals to examine certain parts of the body and to study the differences existing between healthy and unhealthy tissuesas well as tissues that present abnormal conditions. MRI allows the creation of detailed three-dimensional images to examine organs such as the brain, spine, joints such as the knee, shoulder, hip, wrist and ankle; the abdomen, pelvic region, breasts, blood vessels and heart, among other regions.

To perform a MRI examinationis used, a magnetic resonance medical equipment. In this procedure, the patient is placed inside an MRI scanner. We can define it as a large circular apparatus which is open at both ends. Once the patient is inside the MRI equipment, a series of signals and radio waves are produced and detected by a receiver inside the device. Subsequently, the cross-sectional images of tissues that are visualized through a computer.

What is this process like and what does MRI detect? In the following article, we explain the origin of this medical technique and how it works, as well as its advantages and limitations.

Origin of magnetic resonance imaging

In 1946, Felix Bloch and Edward Purcell independently discovered the magnetic resonance phenomenonfor which they were awarded the Nobel Prize in Physics in 1952. But, actually, its development as a chemical and physical molecular analysis procedure took place in the period between 1950 and 1970. Beginning in 1971, Raymond Damadian demonstrated that MRI relaxation times differed between healthy and tumor tissues, which led scientists to begin to study this technique for the diagnosis of diseases.

At the same time, in 1973 Hounsfield introduced another of today's most widely used medical techniques: computed tomography (CT), which uses X-rays. The success of TAC The results showed that hospitals were willing to invest in the development of new diagnostic imaging equipment, which also drove the development of MRI. In the same year, Paul Lauterbur obtained the first magnetic resonance image, using a back projection technique similar to that of computed axial tomography.

As of 1980sthe gradual implementation of MRI in clinical practiceto the current situation. Today, magnetic resonance imaging is one of the most widely used diagnostic imaging techniques.

How does MRI work?

The human body is composed mainly of water and fat, so that hydrogen atoms account for 63% of the total number of atoms in the body. The hydrogen nucleuswhich consists of a proton, is used in magnetic resonance imaging because it acts like a powerful magnet that generates a magnetic field around the patient's body. MRI is a diagnostic imaging method based on the absorption and emission of energy in the form of a set of radiofrequency signals within the electromagnetic radiation spectrum. The radiofrequency used in MRI produces frequencies of between 15 and 80 megahertz, making it a non-ionizing radiation that is harmless to the body.

In an MRI exam, the patient is placed inside an MRI scanner. magnetic resonance scanner which produces radio waves that interact with the protons, generating a series of radio frequency signals that are detected by a receiver inside the device. All these signals emitted and detected by the scanner's antenna are processed in a computer, where they are detailed images of the fabrics and inside the organism that allow the medical diagnosis to be made.

Specifically, a MRI equipment consists of the following elements:

• External magnet
• Magnetic field gradients
• Radio frequency transmitter
• Radio frequency receiving antennas
• Computer

How is an MRI exam performed?

To perform an MRI exam, a medical MRI machine is used, where the patient is introduced into a large device that has a circular shape and is open at the ends. This procedure is performed in a special room housing the MRI system or scanner. A member of the MRI staff accompanies the patient into the room, where he/she will be asked to lie down on a padded table and then be introduced into the machine to begin the MRI diagnosis.

Before the test

The majority of diagnoses have a duration between 15 and 45 minutesdepending on the part of the body to be tested and the number of images needed. Before the test, the person must partially or completely undress and is provided with a gown that has no buttons or metal fasteners. It is important to leave all metal objects and other items that could be affected by the magnetic field outside the MRI room. For example, keys, jewelry, cell phones, credit cards or watches.

During the test

It is important that the patient remains still and relaxed.. In some examinations, an intravenous injection of a contrast material called gadolinium to obtain a clearer image of the area to be examined. To do this, at the beginning of the medical test, a nurse will place an intravenous line into a vein in the patient's arm or hand using a small needle.

On the other hand, it should be noted that the magnetic resonance system can produce certain loud noises during the procedure. To prevent any problems associated with noise, earplugs are provided. For the duration of the diagnosis, the patient will be monitored at all times and will be able to communicate with a medical professional via an intercom.

After the test

Once you have completed the exam, images will be reviewed by a radiologistwho will subsequently inform the physician of the results of the MRI examination.

MRI in medical practice

Magnetic resonance imaging is a procedure used to study the differences that exist between healthy and unhealthy tissues, as well as other regions of the human body that present abnormal conditions. Nowadays, it is one of the most widely used diagnostic imaging techniques and it allows for detect a large number of diseases and abnormalities in virtually all regions of the body:

• HeadCentral nervous system, orbit, face and skull.
• Neck.
• SpineSpinal cord, meninges, bone spine and intervertebral discs.
• Chestespecially at the cardiovascular level.
• Abdomenliver, biliary tract, spleen, pancreas, urinary tract, genital tract and pelvis.
• Large joints and extremities.

What does MRI detect?

MRI is often prioritized over CT scanning when the physician needs to have more detail about the soft tissues. For example, it helps to obtain images of abnormalities in the brain, spinal cord, muscles and liver. It is also very useful in identifying tumors in these tissues. MRI has the following clinical applications:

1. Morphological applicationsDefinition of congenital anomalies, traumatic pathology, detection and extension of tumors,
   degenerative diseases, vascular pathology, inflammatory processes and infectious pathology.
2. Functional applicationsThese are functional brain MRI studies and functional cardiac studies.
3. Tissue analysis applicationsMRI spectroscopy, chemical shift studies, perfusion studies and diffusion studies.

This diagnostic technique is also used to analyze other types of conditions and as an alternative to other procedures that present greater risks:

• Measuring the presence of certain molecules in the brain that distinguish a tumor from an abscess.
• Identify alterations in the female genitalia and fractures in the hip and pelvis.
• Perform the valuation of certain common joint anomaliessuch as torn knee ligaments or cartilage and sprains.
• Study and evaluate bleeding and other infections.
• MRI is applied when the The risks of performing a CT scan are high.. Especially, it can be used in people who have had a reaction to iodinated contrast media in a CT scan and for pregnant women, because radiation can cause problems in the fetus.

Types of magnetic resonance imaging

We can distinguish between different types of MRI:

Functional Magnetic Resonance Imaging or fMRI

fMRI is used for observe the structures and functioning of the brain. It measures the small changes in blood flow that occur in brain activity. This type of test helps detect abnormalities within the brain that cannot be found with other imaging techniques.

Perfusion magnetic resonance imaging

Professionals can use this type of magnetic resonance imaging for to estimate the blood flow in a particular area. It is useful in determining whether the blood supply to the brain has been reduced when a stroke. It also serves to identify areas where blood flow is increased, such as in the case of the tumors.

Diffusion-weighted magnetic resonance imaging

It is used to detect changes in the water movements of cells that are not functioning normally. It helps to identifying early stages of strokes, detect brain disordersanalyze whether a tumor has spread o differentiate a brain abscess from a tumor.

Magnetic resonance spectroscopy

This type of test is used for detect brain disordersThe method can distinguish between dead tissue within an abscess and the presence of multiplying cells within a tumor. Specifically, this method can distinguish between dead tissue within an abscess and the presence of multiplying cells within a tumor. In turn, it is used to to assess metabolic disorders of the muscles and nervous system.

Magnetic resonance angiography

Provides detailed images of blood vesselsIt is used to assess the blood vessels of the brain, heart, abdominal organs, arms and legs. In particular, this technique is used to analyze aortic aneurysms, aortic dissection, narrowing of the arteries of the extremities, thrombi in the veins of the extremities, blood flow to tumors and tumors affecting the blood vessels.

Magnetic resonance venography

This is a magnetic resonance imaging of veins. Detects the cerebral venous thrombosisThe presence of thrombi in a vein that carries blood from the brain.

Advantages of magnetic resonance imaging

MRI has established itself as a safe, accurate and effective diagnostic imaging method. Currently, MRI stands out for offering many advantages, which has led to the prioritization of this technique over other procedures, especially computed tomography, radiological tests and ultrasoundsWhat are the advantages?

• It is a non-invasive, safe and painless scanning technique. It does not use ionizing radiation or nephrotoxic contrast media and does not produce adverse effects in patients.
• MRI is a test that helps to assess both the structure of an organ and its functioning.
• Provides a high spatial, temporal and tissue resolution for tissue differentiationTherefore, MRI has an important role in the early diagnosis of soft tissue diseases.
• It has three-dimensional capabilityThe system provides detailed, cross-sectional images of the tissues and organs to be examined. In this way, it makes it possible to detect anomalies that could be hidden by the bones when other diagnostic methods are used.
• Allows you to to perform functional studies. Functional Magnetic Resonance Imaging or fMRI is a medical test used to examine the parts of the brain that are handling critical functions, evaluate the effects of stroke or other diseases, as well as guide brain treatment.

Limitations and risks of magnetic resonance imaging

However, it also presents some risks and disadvantages that are important to analyze:

Increased diagnostic time and cost

The time required to perform an MRI scan is high. For this reason, CT is often used in emergency situations, such as severe injuries and strokes. In turn, the economic cost is higher and there is a limitation in availability compared to other imaging techniques.

Anxiety and claustrophobia problems

The magnetic resonance equipment is a small, enclosed spaceThe patient may feel a feeling of claustrophobia or anxiety. For this purpose, the patient may be given an anxiolytic, such as alprazolam or lorazepam, prior to the start of the examination.

Currently, there are also open magnetic resonance scannerswhich offer an open side and a wider interior. This makes people can reduce claustrophobia and obese people can access more easily. However, the images produced may be of lower quality. But despite this, such open devices can be used for diagnostics.

Magnetic field effects

The presence of implanted metallic devices or materials in the patient's body can produce certain adverse effects. The magnetic field used in this medical technique is very powerful and always active, which can cause the devices to shift, overheat or malfunction. In addition, they can also distort the images generated.

Among these devices are the cardiac pacemakers, defibrillators, cochlear implants and metallic magnetic clicks used in the treatment of aneurysms. However, other devices such as dental implants, hip replacements or spinal straightening rods have none of these effects. Therefore, it is important that people who have any implanted devices inform the physician before making an IMR diagnosis.

Reactions to contrast agent

The gadolinium contrast media can lead to a number of reactionsThe most common symptoms are headache, nausea, pain and cold sensation in the area where the injection is made, distortion of taste and dizziness. However, it should be pointed out that these contrast agents present lesser reactions than iodinated contrast media used in CT scans and CT angiography.

In conclusion, magnetic resonance imaging is a diagnostic imaging technique that provides detailed, cross-sectional imaging examinations that are essential in the detection of disease and for studying virtually all regions of the human body.

Kiko Ramos

CEO of 4D Médica. Expert in marketing and distribution of medical equipment.

All about ultrasound: What are ultrasound scans, how do they work and types?

by 4D Medical | Oct 23, 2024 | Medical equipment, Medical techniques

An ultrasound, also called a sonogram or ultrasound, is an ultrasound scan. diagnostic imaging test that uses the sound waves to create images of organs, tissues and internal structures of the organism. It is a simple, safe and non-invasive technique which allows health professionals to analyze and observe the inside of the body without surgery. In other words, it is a diagnostic technique that no need to make any incisions or use ionizing radiationas in the case of X-rays.

It stands out for being a comfortable, economical and painless test. It is mainly used for diagnose various medical conditionshealth monitoring and development of the baby during pregnancy and guide certain medical proceduresThe main objective is to perform biopsies, tissue extraction and other techniques that require diagnostic imaging.

How does an ultrasound scan work?

An ultrasound is a technique that emits a series of mechanical waves that have a frequency above the hearing ability of the human ear and allow create two-dimensional and three-dimensional images. These images are called sonograms and are performed with specific equipment. The medical devices that allow these diagnoses to be performed are ultrasound scanners. They have a tool rod-shaped which is known as transducerr and is responsible for detecting the waves produced in the different tissues, organs and fluids of the body. These are then picked up again by the transducer and converted into electrical signals.

In order to analyze the waves, a special gel on the skin in the area to be examined. Through the use of a computer, these signals are processed to create a real-time image of internal structures of the organism. The images produced are visualized on the screen and provide information on movements that are occurring, the distance at which a fabric is locatedas well as its size, shape and composition.

Types of ultrasound scans: Uses and main differences

We can find different types of ultrasound: ultrasound in pregnancy, diagnostic medical ultrasound, guided ultrasound, as well as 3D and 4D ultrasound. Let's see their main differences:

Ultrasound in pregnancy

Ultrasound in pregnancy, also known as obstetrical ultrasound, is a diagnostic imaging test that provides the visualization of the fetus inside the mother's uterus. As it is an ultrasound technique that does not involve radiation, it is a safe technique for mother and baby.

What is fetal ultrasound used for?

It allows analysis of the baby's growth, health and general development. In particular, it provides the following information:

• Confirmation of pregnancy.
• Verification of multiple pregnancy (twins and triplets).
• Knowledge of the gestational age. That is, how far along the pregnancy is.
• Analysis of the sizethe position of the fetus, the growth and the sex of the baby.
• Diagnosis of congenital defects in the various parts of the baby's body, such as the brain, heart or spinal cord.
• Study of the existing amount of amniotic fluid. It is essential for the development of the baby's lungs and bones, as well as to protect the baby from injury.
• Identify problems in the placenta, uterus, cervix and ovaries of the mother.
• Information on possible signs that could indicate an increase in the number of risk of Down syndrome.

Diagnostic medical ultrasound

Diagnostic medical ultrasound is essential for the diagnosis and treatment of study of diseases or possible health problems in the patient. This type of test is used when a person detects certain symptoms that are important to analyze. Using this type of ultrasound, medical professionals can study various medical conditions involving different parts of the body. Depending on the area to be analyzedwe can distinguish different modalities of diagnostic medical ultrasound scans:

• Abdominal ultrasoundIt focuses on the observation of the internal structure of the abdomen. It allows to analyze organs such as the pancreas, kidneys, liver, gallbladder and spleen.
• Vaginal ultrasoundVaginal ultrasound: This test is used to analyze the uterus, ovaries, endometrium, cervix, fallopian tubes and pelvic area of the woman. Vaginal or tansvaginal ultrasound is used to detect possible gynecological conditions, such as the presence of ovarian cysts, fibroids and uterine fibroids, abnormalities in the menstrual cycle, certain types of infertility and pelvic pain.
• Rectal ultrasoundRectal examination: Consists in the evaluation of the rectum to study the prostate and bladder function.
• Renal ultrasoundKidney ultrasound: Evaluates the condition of the kidneys, both the size, location and shape, as well as their adjacent structures. This type of ultrasound helps detect the presence of tumors, cysts and renal obstructions.
• Breast ultrasoundIt is used to detect abnormalities in the breast tissue, such as the presence of cysts. It is often used as a backup technique after mammography.
• Cervical and thyroid ultrasoundAnalyzes the functioning of the thyroid gland, which is located in the neck. It is essential to study possible health problems that may arise, such as the appearance of nodules, cysts and structural alterations. It is also used to analyze the salivary glands.
• Doppler or vascular ultrasoundThe speed and direction of blood flow in the heart and blood vessels can be analyzed with this ultrasound. It allows to measure the blood circulation in the different organs of the body, as well as the neck, arms and legs. It is an essential test to diagnose possible blockages, narrowing and problems in the circulatory system.
• Muscle ultrasoundMusculoskeletal ultrasound: This ultrasound is also called musculoskeletal ultrasound. It explores the different muscles, tendons, ligaments, bursae, cartilage, joints and bone surfaces, making it possible to detect the presence of injuries, tendinitis, degenerative problems and other conditions of the muscular tissues.

Guided ultrasound

Guided ultrasound is a technique used for the diagnosis and treatment of development of ultrasound-guided procedures. It is used to guide health care professionals in the Performing tissue biopsies, tissue aspiration and removal, catheter placement, abscess drainage and percutaneous injections.. This technique consists of the introduction of a needle or catheter into the area of the body to be tested. Transducer advancement is controlled in real time, allowing the needle to be steered for more accurate medical diagnosis.

This type of ultrasound can be performed in two ways: through devices adapted to the probes or through the hands-free techniquewhere the professional holds the needle with one hand and the probe with the other hand.

3D and 4D ultrasound

The technological advances in the field of medicine allow the images generated in an ultrasound scan to be displayed in 3D and 4D. The 3D ultrasound scans emerged at the end of the 1990s and offer a wide range of high-resolution static images with a three-dimensional perspective. Currently, the systems used are based on mechanical transducerswhich make it possible to obtain images in the three perpendicular planes. Thus, in the image, the following can be seen transverse, longitudinal and coronal sections. As for the 4D ultrasound scansincorporate a technology that captures motion in real timeThis provides a closer and more realistic reproduction of what is happening inside the organism.

In which cases are 3D and 4D ultrasound scans used?

The 3D ultrasound scans are used in pregnancy and in various specialties. such as gastroenterology, gynecology and obstetrics, breast and uterine pathology and cardiology. It also plays an essential role in vascular surgery, urology, rheumatology and traumatology.

For their part, the 4D ultrasound scans are used during pregnancy to analyze the baby's development. By providing real-time motion, shows the gestures and movements made by the baby inside the uterus and also serves to detect possible problems and anomalies. It is recommended to be performed around the 28th week of gestation.This is the moment when the fetus is more developed and its features are more similar to those of a newborn. At the same time, in 4D ultrasounds, it is essential that there is a sufficient amount of amniotic fluid. This is a fundamental aspect for the ultrasound waves to be transmitted properly. Otherwise, the image will be displayed with lower quality, so it would not be advisable to use this technique.

However, it should be noted that 3D and 4D ultrasound scans are not a substitute for follow-up ultrasound scans. which must be performed at 12, 20 and 32 weeks of gestation. Therefore, it is a complementary test for more information on fetal growth.

Innovations in the field of ultrasound

In the field of diagnostic imaging, the ultrasound scanners are the devices used to perform ultrasound scans. In recent years, numerous advances have led to the development of a new type of ultrasound system. medical equipment adapted to new needs of medical centers, hospitals and health professionals.

In addition to the traditional ultrasound scanners that allow a simple and safe test to be performed, the following have emerged new generation ultrasound scanners that use the latest technology and are equipped with artificial intelligence. This type of ultrasound scanners are portable and are characterized by the fact that they can be used completely remotely. In this way, professionals do not have to be present in medical centers and can reach many more regions and patients. Undoubtedly, a a key aspect to boost telemedicine and create fast, complete and accurate diagnostics.

In conclusion, ultrasound scans are one of the most important The most widely used medical diagnostic imaging techniques in use today. This is because it is an easy, safe and non-invasive test that is very useful for diagnosing certain medical conditions, for analyzing the development of the baby during pregnancy and also as a support technique for other procedures. In most cases, ultrasound is part of the first diagnosis to then evaluate how to proceed and what other tests should be performed when treating an ailment or disease.

Kiko Ramos

CEO of 4D Médica. Expert in marketing and distribution of medical equipment.