What is Magnetic Resonance Venography (MRV) of the Brain?
Magnetic resonance venography of the brain is a non-invasive, painless diagnostic imaging procedure that uses radio waves and a strong magnetic field to create detailed images of the veins in your brain. Typically, a contrast dye injection is used during the procedure to enhance vein visibility.
How does an MRV Work?
MRV scanning involves the use of radio waves that temporarily realign hydrogen atoms in the body without causing any chemical changes. As the hydrogen atoms return to their normal position, they emit varying amounts of energy depending on the type of tissue they are in. The MRV scanner captures this energy variation and creates detailed images of the veins in the brain based on this information.
Uses of Magnetic Resonance Venography of the Brain
An MRV of the brain may be ordered by your doctor to help diagnose conditions that impair normal venous drainage from the brain, including:
- Cerebral venous thrombosis (blood clots in the brain)
- Structural vein abnormalities
- Intracranial hypertension
- Blood flow problems
Indications for Magnetic Resonance Venography of the Brain
An MRV may be ordered to evaluate symptoms such as:
- Progressive unilateral, throbbing headache
- Sudden onset headache (thunderclap headache)
- Altered sensation
Preparation for Magnetic Resonance Venography (MRV) of the Brain
- Inform your doctor regarding any health conditions, previous surgeries, implants or metal placed within your body, the likelihood of pregnancy, and any allergies.
- Leave all jewelry at home. Wear loose-fitting comfortable clothing that does not contain any metal fasteners.
- Follow the dietary restrictions given by your doctor.
- Continue to take your regular medications unless otherwise specified.
Procedure for Magnetic Resonance Venography (MRV) of the Brain
Magnetic resonance venography of the brain is performed in an MRI machine and involves the following basic steps:
- You will be placed comfortably on a movable scanning table.
- Bolsters or straps may be used to help you remain still.
- A device containing coils that send and receive radio waves is placed around your head.
- You may be offered earplugs to muffle the noises made by the MRI machine, or you can choose to listen to music through headphones during the procedure.
- An IV line will be placed into your arm to inject the contrast material as needed.
- The scanning table will be moved into the magnet area of the MRI machine.
- The technologist will perform the examination from another room, taking multiple pictures of the brain that each last several minutes.
- You will be required to remain as still as possible to obtain the clearest images.
- A microphone in the MRI machine allows you to talk to the technologist.
- The entire procedure is completed in 45 to 60 minutes.
What happens after Magnetic Resonance Venography (MRV) of the Brain?
You can return to your routine activities and resume your normal diet immediately after the procedure. If sedation was provided to help you relax, you may have to wait until the effects wear off before returning to your usual activities. A radiologist or trained doctor will analyze the images and send the report to your family physician, who will share the results with you.
Risks of Magnetic Resonance Venography (MRV) of the Brain
- The strong magnetic field produced by the MRV procedure does not cause any harmful effects; however, implanted devices can distort the images.
- You may have an allergic reaction to contrast dye. These reactions are usually mild and can be easily controlled with medication.
Benefits of Magnetic Resonance Venography (MRV) of the Brain
- Produces highly detailed images of the veins in the brain and associated cranial structures
- Detects venous abnormalities which may be obscured in other imaging studies
- Virtually no side effects as there is no exposure to harmful radiation