Unexplained weight loss is defined as the unintentional loss of at least 10 pounds or 5 percent of body weight over a period of 6 to 12 months. This would be equivalent to a 200-pound man losing 10 pounds or a 130-pound woman losing six to seven pounds.
What It Is. Magnetic resonance imaging (MRI) of the brain is a safe and painless test that uses a magnetic field and radio waves to produce detailed images of the brain and the brain stem. An MRI differs from a CAT scan (also called a CT scan or a computed axial tomography scan) because it does not use radiation.
Magnetic resonance imaging (MRI) is a radiological study that obtains images with magnets and radio waves. Unlike X-rays and CT scans, MRI uses no radiation. There are three types of MRI machines: closed, open and standing. Closed and open are most commonly used. Closed MRIs are the oldest type of MRI machines. During the procedure, the patient lies down on a table, which slides into a large tube. The patient is asked to lie very still during the test.