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How MRI, CT Scan, and PET Scan are used to Diagnose Alzheimer’s disease

MRI (Magnetic resonance imaging), CT Scans (Computer Tomography), and PET (Positron Emission Tomography) are done to rule out other possible medical conditions, such as a stroke. Also, the brains of people with Alzheimer’s disease are smaller in some spots then brains of people without Alzheimer’s disease. This can be seen on MRI and CT scans.

An MRI scan (Magnetic resonance imaging) takes pictures of the brain, spinal cord, optic nerve (the nerve that connects the eye to the brain), and other parts of the body.  An MRI machine uses very large magnets and radio waves to take these pictures. This machine does not use x-rays or radiation, unlike CT scans (Computerized tomography scans). Having an MRI done is painless. The patient will lie down on a table and the table will move the patient into the machine. If the patient has a pacemaker, metal implants, or any other metal on them, they are not able to have an MRI done.

A CT Scan (Computer Tomography) takes three dimensional pictures of the brain, spinal cord, and other parts of your body. CT scans use x-rays to take these pictures. CT scans are often used when a patient is not able to have an MRI (Magnetic Resonance Imaging). Before the CT scan, the patient will be injected with a special dye. This dye helps show how the brain and other organs are functioning.  CT scans are painless: the patient will lie down on a table and the table will move the patient into the machine.

A PET scan (Position Emission Tomography) is used to check blood flow in the brain.  For a PET scan, radioactive dye is injected into the patient. Next, various electrodes are attached to the patient’s scalp. During the scan a computer takes pictures of the brain.

Additional resources that provide more information on MRI (Magnetic Resonance Imaging), CT Scan (Computed tomography), and PET Scan (Positron Emission Tomography):