antigen specific immunity attributable to the production of antibody and of specific immune T lymphocytes (responsible for cell-mediated immunity), following exposure to an antigen, or passive transfer of antibody or immune lymphoid cells (adoptive immunity).
Types of X-rays and Scans. MRA (Magnetic Resonance Angiography) MRAâa type of magnetic resonance imaging (MRI) study that is obtained with the same scanning machineâuses a strong magnetic field combined with radiofrequency waves to create highly detailed images of blood vessels in the body. (MRA is most often used to examine vessels in the brain, neck, kidneys, and legs.) The resulting scans, which provide information about blood flow and the condition of blood vessel walls, may then be saved on a computer or on film and examined for abnormalities.
In many cases, the MRA provides information that a doctor canât detect using an ultrasound, regular X-ray, or CT scan. The exam is also noninvasive. The images may be stored on a computer or printed on film. The difference between an MRI and an MRA is that an MRA is used specifically to examine blood vessels.