MRI: types and characteristics

An MRI is a test that uses a magnetic field and radio waves to create detailed images of organs and tissues. This study is not invasive and allows diagnosing tumors, malformations, and various health problems in different parts of the body¹.

Types of MRI

This study can be done in different anatomical regions, with the same function and results. The types of MRI by area can be:

  • MRI of the abdomen
  • Cervical MRI
  • chest MRI
  • MRI of the head
  • MRI of the heart
  • lumbar MRI
  • pelvic MRI
  • MR angiography
  • MR venography

Magnetic resonance imaging of the skull and spinal cord allows the observation of neurological disorders, tumors, brain injuries due to trauma, ophthalmological disorders, etc. Likewise, functional magnetic resonance imaging (MRI) is a study that is also taken in the skull, however, it can measure the changes in blood flow that occur when there is brain activity and allows locating the parts of the brain that work in critical conditions.

For this type of study, the patient may be asked to move fingers or toes to facilitate the search for neural abnormalities.

Many specialists use magnetic resonance imaging to confirm diagnoses or to know in detail the invasion of a tumor; such is the case of breast MRIs, which are ordered to the patient if greater clarity is required after a mammogram.

Magnetic resonance imaging of the heart and blood vessels facilitates the diagnosis of cardiac dysfunction, damage due to cardiorespiratory arrest, blockage of blood vessels, etc. In the same way, it can show images in other organs such as:

  • Liver
  • Kidneys
  • Spleen
  • Pancreas
  • Uterus
  • Ovary
  • Prostate

other specifications

Positions in different regions of the body and the need for an intravenous contrast medium may vary. The contrast serves to more clearly identify certain areas of the body; the most common in this study is gadolinium², due to its low risk of allergic reaction. However, it is important to communicate if the patient lives with chronic conditions that may be contraindicated for the use of contrast.

The duration of this study can vary between 15 minutes to 1 hour, therefore, there is the possibility of sedation to avoid situations that encourage movement in pediatric patients with anxiety or claustrophobia problems.

What does it consist of?

The signals emitted by the electromagnetic waves are collected and translated into images that can be seen on a monitor, allowing the professional to study them.

The MRI apparatus is tubular in shape and open at both ends. To perform the test, the patient must lie on a mobile table that will slide into the tube. The device creates a strong magnetic field around the patient, sending radio waves into the body. However, the patient will feel no pain at any time during the test.

In any case, the MRI can last between 15 and 60 minutes, and the patient must remain completely still, otherwise, the images may be blurred.

Why is it done?

Magnetic resonance allows experts to perfectly differentiate the different anatomical structures to make a clearer and more complete diagnosis. Thanks to this ability to observe tissues and organs in detail, the specialist can diagnose the presence of injuries or diseases in the area studied.

There are several reasons why a person may undergo an MRI: 

  • MRI of the head and spinal cord: multiple sclerosis,  aneurysms, eye disorders, ear disorders, stroke, tumors, head injuries…
  • MRI of the chest: breasts and breast cancer, heart function, blood blockages…
  • MRI of internal organs: spleen, kidneys, liver, prostate, ovaries, spleen…
  • MRI of bones and joints: bone infections, soft tissue tumors, ligamentous injuries, spinal abnormalities, trauma. 

Preparation for MRI

The patient, before undergoing the test, can eat normally and continue taking the usual drugs. In some cases, depending on the area of ​​the body to be examined, it is necessary for the patient to be without eating or drinking for a period of four to six hours before the exam, but in that case, the doctor will indicate it.

Generally, the patient should change into a hospital gown and remove any objects that may affect the MRI images, such as the following:

  • metal objects
  • watches
  • hair clips
  • Earphones
  • Dentures
  • underwire bra
  • Cosmetics that have metal particles in their composition

What does it feel like during the exam?

This test usually lasts between 30 and 60 minutes. It does not cause pain but if the person is afraid of closed spaces it can cause claustrophobia. In that case, they may give the patient medicine to make them sleepy and less anxious.

In any case, it is important that the patient remain still during the exam.

MRI Risks

MRI does not use any radiation. The type of contrast that is usually used is gadolinium, which is very safe and rarely causes any type of allergic reaction.

However, the strong magnetic fields that are created during the test can cause some implants such as pacemakers to not work as well. Magnets can also cause a piece of metal inside the body to move or change position.

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