Brain Scan Vs. MRI

A variety of methods can be used to peer inside the skull to assess and evaluate the structure and function of the brain. Among the different types of scanning technologies, Magnetic Resonance Imaging (MRI) and Computerized Tomography (CT) brain scans are the most common.

Uses

• A CT brain scan is commonly used to detect the following problems within the skull: bleeding, fractures, blood clots, brain tumors, enlarged cavities, diseases and malformations. An MRI is used to examine the brain anatomy, evaluate brain mapping, monitor the growth of brain tumors and assess the effects of damage to the brain.

Function

• With a CT brain scan, numerous x-ray beams will measure the amount of radiation absorbed by the body; the data is grouped together to create a two-dimensional cross-section image of the brain. An MRI uses radio frequency pulses and a strong magnetic field to generate brain images from several different angles.

Procedure

• For both a CT brain scan and an MRI, the patient will lie flat on an examination table as the machine rotates around the body; the patient may be injected with contrast material. With an MRI, patients may be asked to perform simple tasks during the test.

Risks

• With a CT scan, there is a small risk of cancer related to the radiation exposure. There are virtually no risks associated with an MRI, although metal objects are not allowed near the unit. Pregnant women are advised not to receive a CT scan or MRI unless medically necessary.

Limitations

• A CT scan provides a less detailed view of the brain than an MRI, but an MRI can only achieve high-quality images if the patient remains absolutely still during the test. Very large people may be unable to fit inside both the CT and MRI machines.