2 - Fundamentals of Magnetic Resonance Imaging

Abstract

The root of nuclear magnetic resonance (NMR) or magnetic resonance imaging (MRI) goes back to World War II. The commonly used detection method during the first two decades of NMR work exploited the principles of continuous wave excitation. MRI is based on the physical principle of nuclear magnetic resonance. In MRI, it is the protons in the water molecules of a patient's tissue that are the source of the signal. The spatial information needed to form images from magnetic resonance is obtained by placing magnetic field gradient coils on the inside of the magnet. The magnet in MRI is responsible for generating the static magnetic field. The gradient coils create a gradient, which is superimposed upon the main magnetic field. NMR measurements are often given in a unit less quantity called chemical shift. MRI is one of the most important imaging technologies found in most modern hospitals. The chief use of clinical MRI is for imaging the brain and spineOver the years, MRI has assisted physicians in diagnosis, treatment, and presurgical treatments. The main advantage of MRI as compared to other imaging tools is that it does not require exposure of the human body to ionizing radiation, which makes it very safe. The MRI signals are also very sensitive to different parts of tissues.