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.
Difference between Open and Closed MRI. MRI stands for magnetic resonance imaging. MRI is a technique used in medicine to get a picture of what is going on inside the human organism. While closed MRI is designed to put the human body in the enclosed tube, open MRI allows for making scans without using this tube. There are more differences between the two types of MRI.