MRI of the head

• A
• B
• C
• D
• E
• F
• G
• H
• I
• J
• K
• L
• M
• N
• O
• P
• Q
• R
• S
• T
• U
• V
• W
• X

Brain

Lobes of the brain

MRI scans

An MRI of the head is a noninvasive procedure that uses powerful magnets and radio waves to construct clear, detailed pictures of brain tissues.

Conventional radiography and computed tomographic (CT) imaging use potentially harmful radiation (x-rays) that passes through a patient to generate images. Magnetic resonance imaging (MRI) is based on the magnetic properties of atoms, and there is no exposure to the same type of radiation used in x-rays and CT scans.

A powerful magnet generates a magnetic field roughly 10,000 times stronger than the Earth's. A very small percentage of hydrogen atoms within the body will align with this field. Radio wave pulses are broadcast towards the aligned hydrogen atoms in tissues of interest, returning a signal of their own. The slight differences of those signals from different tissues enables MRI to tell the difference between various organs, and potentially, provide contrast between benign and malignant tissue.

Any imaging angle, or "slice", can be projected, and then stored in a computer or printed on film. MRI can easily be performed through clothing and bones. However, certain types of metal in or around the area of interest can cause significant errors in the reconstructed images. These errors are called artifacts.

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

Since MRI makes use of radio waves very close in frequency to those of ordinary FM radio stations, the scanner must be located within a specially shielded room to avoid outside interference.

You will lie on a narrow table which slides into a large tunnel-like tube within the scanner. In addition, a small device may be placed around the head. This is a special body coil which sends and receives the radio wave pulses. It is designed to improve the quality of the images.

If contrast dye is used, it will be injected into a small vein of the hand or forearm. A technologist will operate the machine and observe you during the entire study from an adjacent room.