Magnetic resonance imaging (MRI) of the spine and brain (2023)

What is Magnetic Resonance Imaging (MRI)?

(brain MRI, spine MRI)

Magnetic resonance imaging (MRI) is a diagnostic procedure that uses a combination of a large magnet, radio frequencies and a computer to create detailed images of organs and structures in the body. not howX rayorComputed tomography(CT scan), MRI does not use ionizing radiation. Some MRI machines look like narrow tunnels, while others are more spacious or wider. MRI scans can take anywhere from 30 minutes to two hours.

How does an MRI work?

The MRI machine is a large cylindrical (tube-shaped) machine that creates a strong magnetic field around the patient. Along with radio waves, the magnetic field changes the natural alignment of hydrogen atoms in the body. Pulses of radio waves sent from a scanner knock the nuclei of your atoms out of their normal positions. When the cores snap back into place, they emit radio signals. These signals are received by a computer, which analyzes them and converts them into a two-dimensional (2D) image of the structure of the body or organ being examined.

Magnetic resonance imaging (MRI) can be used insteadComputed tomography (CT)in situations where organs or soft tissues are being examined, as MRI is better able to differentiate between normal and abnormal soft tissues.

New applications and indications for MRI have contributed to the development of additional MRI technologies.Magnetresonanzangiografia (MRA)is a new non-invasive method of assessing blood flow through arteries (does not pierce the skin). MRA can also be used for detectionintracranial aneurysms (inside the brain)and vascular malformations (abnormalities of blood vessels in the brain, spinal cord, or other parts of the body).

Magnetic resonance spectroscopy (MRS) is another non-invasive procedure used to evaluate chemical abnormalities in body tissues, such as the brain. MRS can be used to detect disorders such asHIV infection in the brain,AVC,head injury, for,Alzheimer's disease, tumors andMultiple sclerosis.

Functional brain magnetic resonance imaging (fMRI) is used to determine the specific location in the brain where a specific function, such as language or memory, occurs. The general areas of the brain where these functions occur are known, but the exact location can vary from person to person. During the functional brain MRI, you will be asked to perform a specific task, such as B. recite the Pledge of Allegiance while the scan is being performed. By identifying the functional center in the brain, doctors can plan surgery or other treatments for a specific brain disorder.

Anatomy of the Vertebral Column

The spine, also known as the spinal canal or spinal canal, is made up of 33 vertebrae, which are separated by intervertebral discs and divided into different areas.

The cervical area consists of 7 vertebrae in the neck.
The thoracic area consists of 12 vertebrae in the thoracic area.
The lumbar region consists of 5 vertebrae in the lower back.
The sacrum has 5 small fused vertebrae.
The 4 coccygeal vertebrae fuse into one bone called the coccyx or coccyx.

The spinal cord, an important part of the central nervous system, is located in the spinal canal and extends from the base of the skull to the top of the lower back. The spinal cord is surrounded by the bones of the spine and a sac containing cerebrospinal fluid. The spinal cord transmits sensory and movement signals to and from the brain and controls many reflexes.

Anatomia Cerebral

The central nervous system (CNS) consists of the brain and spinal cord. The brain is an important organ that controls thinking, memory, emotions, touch, motor skills, vision, breathing, temperature, hunger and all other processes that regulate our body.

What are the different parts of the brain?

The brain can be divided into the cerebrum, brainstem and cerebellum:

brain.The brain (supratentorial or frontal part of the brain) consists of the right and left hemispheres. Brain functions include: initiation of movement, coordination of movement, body temperature, touch, vision, hearing, judgment, reasoning, problem solving, emotions, and learning.
tronco cerebral.The brainstem (midline or midbrain) includes the midbrain, pons, and medulla. The functions of this area include: eye and mouth movement, relaying sensory messages (such as heat, pain, and noise), hunger, breathing, awareness, heart function, body temperature, involuntary muscle movements, sneezing, coughing, vomiting, and swallowing.
cerebellum.The cerebellum (infratentorial or rhombencephalon) is located at the back of the head. Its function is to coordinate voluntary muscle movements and maintain posture, balance and equilibrium.

More specifically, other parts of the brain include:

Pons.The pons is a deep part of the brain located in the brainstem that contains many of the areas controlling eye and facial movements.
Brand.The lowest part of the brainstem, the medulla, is the most vital part of the entire brain and contains important control centers for the heart and lungs.
spinal cord.A large bundle of nerve fibers in the back that extends from the base of the brain to the lower back, the spinal cord carries messages to and from the brain and controls many reflexes.
Frontallapp.The frontal lobe, the largest section of the brain located at the front of the head, is involved in personality traits and movement.
parietal lobes.The middle part of the brain, the parietal lobe, helps a person identify objects and understand spatial relationships (comparing one's body to objects around the person). The parietal lobe is also involved in the interpretation of pain and touch on the body.
Occipitalppen.The occipital lobe is the back part of the brain responsible for vision.
Temporallappen.The sides of the brain, these temporal lobes, are involved in memory, language, and smell.

What are the reasons for an MRI of the brain or spine?

MRI can be used to examine the brain and/or spinal cord for injuries or the presence of structural abnormalities or other conditions, such as:

Cancer
abscesses
congenital anomalies
aneurysms
venous malformations
bleeding or bleeding in the brain or spinal cord
Subdural hematoma (an area of bleeding just below the dura mater or covering of the brain)
degenerative diseases,Multiple sclerosis, hypoxic encephalopathy (malfunction of the brain due to lack of oxygen) or encephalomyelitis (inflammation or infection of the brain and/or spinal cord)
Hydrocephalus, or fluid in the brain
Herniated or degenerated spinal cord intervertebral discs
Assist in the planning of spinal operations, e.g. B. Decompression of a pinched nerve or spinal fusion

MRI scans can also help pinpoint the specific location of a functional brain center (the specific part of the brain that controls a function such as language or memory) to help treat a brain disorder.

There may be other reasons your doctor might recommend an MRI of your spine or brain.

What are the risks of an MRI?

Since no radiation is used, there is no risk of exposure to ionizing radiation during an MRI scan.

Due to the use of the powerful magnet, patients with certain implanted devices, such as space generators or cochlear implants, require special precautions to have an MRI. The MRI technician will need some information from you about the implanted device, such as: B. the make and model number to determine if an MRI is safe for you. Patients with internal metal objects, such as surgical staples, plates, screws, or wire mesh, may not be candidates for an MRI.

If there is a possibility that you are claustrophobic, ask your doctor to give you an anti-anxiety medication before the MRI scan. You should plan for someone to drive you home after the MRI.

If you are pregnant or think you might be pregnant, you should tell your doctor. To date, there is no information to suggest that an MRI is harmful to an unborn baby; however, MRI scans are not recommended during the first trimester.

A doctor may order the use of a contrast agent during some MRI scans so that the radiologist can better see the internal tissues and blood vessels in the finished images. When using contrast media, there is a risk of allergic reactions. Patients who are allergic or sensitive to contrast media or iodine should notify the radiologist or technician.

Other risks may exist depending on your specific health condition. Be sure to discuss any concerns with your doctor prior to the procedure.

How do I prepare for an MRI?

EAT DRINK:For most MRI scans, you can eat, drink, and take medication as usual. There are some special MRI scans that require certain limitations. As you plan your exam, Johns Hopkins Medical Imaging will provide you with detailed preparation instructions.

CLOTHES: You must wear a full dress and include all personal effects. A locker will be provided for you. Remove all piercings and leave jewelry and valuables at home.

WHAT TO EXPECT: The image takes place inside a large tube-like structure that is open at both ends. To get high-quality images, you must be perfectly still. Due to the high noise of the MRI machine, earplugs are required and provided.

ALLERGIES: If you have had an allergic reaction to the contrast medium that required medical attention, contact your treating physician for the recommended prescription. You will likely take it orally 24, 12, and 2 hours before the exam.

ANTI-ANXIETY DRUGS: If you need anti-anxiety medication due to claustrophobia, contact your treating physician for a prescription. Please note that you will need another person to drive you home.

STRONG MAGNETIC ENVIRONMENT: If you have metal in your body that was not disclosed prior to your appointment, your study may be rescheduled, rescheduled or canceled upon arrival until more information can be obtained.

Depending on your medical condition, your doctor may require a different specific preparation.

When you call to make an appointment, it is extremely important that you let us know if any of the following apply to you:

You have a pacemaker or your heart valves have been replaced
Have any type of implantable pump, e.g. B. an insulin pump
They have vascular coils, filters, stents or clips
You are pregnant or think you might be pregnant
Do you have a body piercing?
You are using a medication patch
You have permanent eyeliner or tattoos
Have you had a gunshot wound before
Have you worked with metal before (e.g. metal grinder or welder)
They have metallic fragments all over their bodies.
You cannot lie down for 30-60 minutes.

What happens during an MRI?

MRI can be performed on an outpatient basis or as part of your hospital stay. Procedures may vary depending on your condition and your doctor's practice.

In general, MRI follows this process:

You are asked to remove any clothing, jewelry, eyeglasses, hearing aids, hairpins, removable dentures or other items that may interfere with the procedure.
If asked to strip, you will be provided with an apron to wear.
If you are having a procedure that involves contrast, an intravenous (IV) line will be placed in your hand or arm to inject the contrast.
You lie down on a scanning table that slides into a large circular opening in the scanning machine. Pillows and straps can be used to prevent movement during the procedure.
The technologist is in another room where the scanner controls are located. However, you have a constant view of the technologist through a window. Speakers inside the scanner allow the technician to communicate and hear you. They have a call button so you can let the technician know if you have a problem during the procedure. The technologist will be watching you at all times and will be in constant communication.
You will be given earplugs or a headset to block out scanner noise. Some headphones can offer music that you can listen to.
During the scanning process, a clicking sound will be heard when the magnetic field is generated and pulses of radio waves are emitted from the scanner.
It is important that you remain very still during the scan, as any movement can cause distortion and affect the quality of the scan.
Depending on the body part being scanned, you may be instructed to hold your breath or not breathe for a few seconds. You will be informed when you can breathe. You must not hold your breath for more than a few seconds.
If your procedure uses contrast dyes, you may experience some effects when the dye is injected into the IV line. These effects include feeling hot or cold, a salty or metallic taste in the mouth, temporary headache, itching, or nausea and/or vomiting. These effects usually only last for a few moments.
You should notify the technician if you experience difficulty breathing, sweating, numbness, or palpitations.
When the scan is complete, the flatbed will slide out of the scanner and you will be lifted off the flatbed.
If an IV line has been inserted for contrast administration, the line will be removed.

While the MRI procedure itself is not painful, standing still during the procedure may cause discomfort or pain, especially with a recent injury or an invasive procedure such as surgery. The technician will take all possible comfort measures and complete the procedure as quickly as possible to minimize any discomfort or pain.

What happens after an MRI?

You must move slowly when rising from the scanner table to avoid dizziness or lightheadedness if lying down during the procedure.

If sedatives were taken for the procedure, you may need to rest until the sedatives wear off. You should also avoid driving.

If contrast medium is used during the procedure, you may be monitored for a period of time for side effects or reactions to the contrast medium, such as itching, swelling, rash, or difficulty breathing.

If you experience pain, redness and/or swelling at the infusion site after returning home, you should notify your doctor as this could indicate an infection or other type of reaction.

Otherwise, after an MRI of the spine and brain, no special care is required. You can resume your usual diet and activities unless your doctor advises you otherwise.

Depending on your particular situation, your doctor may give you additional or alternative post-procedure instructions.