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 test that uses a magnetic field and pulses of radio wave energy to make pictures of organs and structures that are inside the body. During the MRI test (also called an MRI scan), you usually lie on your back on a table that is part of the MRI scanner.Your head, chest, and arms may be held with straps to help you stay still. The table will then slide into the space that contains the magnet.uring the MRI test (also called an MRI scan), you usually lie on your back on a table that is part of the MRI scanner. Your head, chest, and arms may be held with straps to help you stay still. The table will then slide into the space that contains the magnet.