MRI of the head

Injury	Disease	Nutrition	Poison

Symptoms	Surgery	Test	Special Topic

Brain

MRI scans

Lobes of the brain

Overview

Risks

Results

MRI of the head

Alternative Names:

Nuclear magnetic resonance - cranial; Magnetic resonance imaging - cranial; Head MRI scan; MRI - cranial; NMR - cranial; Cranial MRI

What the risks are:

There is no ionizing radiation involved in MRI, and there have been no documented significant side effects of the magnetic fields and radio waves used on the human body to date.

However, people have been harmed in MRI machines when they did not remove metal objects from their clothes or when metal objects were left in the room by others.

Because the effects of strong magnetic fields on a fetus are not well documented at this time, pregnant women are usually advised to avoid MRI scans.

The most common intravenous contrast agent, gadolinium, is very safe, and although there have been documented allergic reactions to it, it is an extremely rare occurrence.

If sedation is used, there are associated risks of over-sedation. The technologist monitors the patient's vital signs, including heart rate and respiration as needed.

Special considerations:

MRI is superior to computed tomography (CT) in most cases where differentiation of soft tissues is necessary. It can view organs without obstruction by bone and foreign bodies. It is capable of showing the tissues from multiple viewpoints and is a noninvasive way to evaluate blood flow.

A CT scan may be preferred for:

Acute trauma of the head and face
Acute (less than 72 hours) neurologic dysfunction
Early symptoms of stroke
Subarachnoid or intracranial hemorrhage (within the first 24 - 48 hours)
Skull bone disorders, disorders involving the bones of the ear

Review Date: 11/3/2004
Reviewed By: Jeffrey J. Brown, MD FACR, Mallinckrodt Institute of Radiology, Washington University School of Medicine, St. Louis, MO. Review provided by VeriMed Healthcare Network.

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