What is the exam?
Magnetic resonance imaging (MRI) is a diagnostic imaging technique that uses a powerful magnetic field and radio frequency waves to obtain images of the structures and internal organs of the body. It allows the inside of the body to be observed from any angle and with much greater clarity, providing a large amount of information.
How is it done?
The exam is performed in an area that is protected from external magnetic fields. The patient must not have any type of metal prosthesis or implant, pacemaker, artificial heart valve or any other metal/magnetic object in his or her body.
The patient lies down on the examination table, following the instructions given by a technician. The table then slides into a tunnel located inside the scanner. A magnetic field is generated and radio waves are then emitted, aimed at the organ to be studied. The generated images are captured and stored digitally. Some MRI scans require contrast medium to be administered. This is a substance that allows a distinction to be made between the different anatomical structures (organs and blood vessels). The contrast medium that is ingested is expelled from the body through the urine.
The magnetic field cannot be felt. It is painless. Some people may feel claustrophobic while they are inside the scanner tunnel. If the patient feels cold, he or she can ask for a blanket. The patient receives earplugs because the noise and buzzing sounds are very loud.
Throughout the exam, the patient is observed and monitored by a technician. Excessive movement may distort the magnetic resonance images. If the patient has difficulty keeping still, he or she may receive a sedative. No recovery period is required (unless the patient has been sedated). After an MRI scan, the patient may resume his or her daily activities.
Patient recommendations:
• Due to the magnetic field, no type of metal/magnetic object is allowed inside the examination room.
• Patients must tell the doctor or MRI technician if he or she has a pacemaker, surgical clips, a prosthesis, metal implants or any other metal object in their body.
• Communicate when sedation or anaesthesia is required.
• The patient must indicate whether he/she is allergic to any kind of medicine.
• The patient must not move during the scan.
• It is very important that the patient brings previous scans of the area of the body where the MRI scan will be performed (e.g., ultrasound, X-rays, MRI scan, CT scan).
Procedures:
MRI Scan of the Abdomen/Kidneys
This is an assessment of the abdominal organs (liver, spleen, pancreas, kidneys, etc.).
Preparation:
6 to 8-hour fasting period.
MRI Scan of the Head
This is a study of the brain parenchyma in the different sequences to assess the white and grey matter and other intra-cranial structures.
Preparation:
6 to 8-hour fasting period.
MRI Scan of the Spinal Column
(Cervical, Thoracic and Lumbar Spine, Sacral Region and Coccyx)
This is a study of the different segments of the spinal column to assess the bones, intervertebral discs and nervous system.
Preparation:
6 to 8-hour fasting period.
Magnetic Resonance Angiography
This is a study of the arteries and/or vessels of a specific area.
Preparation:
6 to 8-hour fasting period.
Magnetic Resonance Cholangiography
This is a study of the gall bladder and bile ducts.
Preparation:
6 to 8-hour fasting period.
MRI Scan of the Orbits
This is a study of the orbital cavity and its contents.
Preparation:
6 to 8-hour fasting period.
MRI Scan of the Pituitary Gland
This is a study of the sellar and parasellar regions and the hypothalamic-pituitary axis.
Preparation:
6 to 8-hour fasting period.
MRI Scan of the Pelvis
This is a study of the pelvic organs (uterus, prostate, bladder and adnexa).
Preparation:
6 to 8-hour fasting period.
MRI Scan of the Neck
This is an assessment of the soft tissues of the neck.
Preparation:
6 to 8-hour fasting period.
MRI Scan of the Joints
(Shoulder, elbow, wrist, hand, knee, tibiotarsal joint, foot, hip, TMJ (temporomandibular joint), etc.)
This is an assessment of the bones, cartilage, ligaments, etc.
Preparation:
6 to 8-hour fasting period.
