©1998-
Magnetic Resonance Imaging (MRI) Scanner
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Comments:
This set of illustrations were created for Scientific American for inclusion in an article about current medical imaging techniques. The artwork was completed in 7 days. The artwork displayed here is shown in a different form to that finally used.
Description:
Magnetic Resonance Imaging (MRI) is primarily used in medical imaging to visualize the structure and function of the body. It provides detailed images of the body in any plane. MR has much greater soft tissue contrast than computed tomography (CT) making it especially useful in neurological, musculoskeletal, cardiovascular, and oncological imaging. Unlike CT it uses no ionizing radiation, but uses a powerful magnetic field to align the magnetization of hydrogen atoms in the body. Radio waves are used to systematically alter the alignment of this magnetization, causing the hydrogen atoms to produce a rotating magnetic field detectable by the scanner. This signal can be manipulated by additional magnetic fields to build up enough information to reconstruct an image of the body.
Magnetic Resonance Spectroscopy is used to measure the levels of different metabolites in body tissues. The MR signal produces a spectrum of resonances that correspond to different molecular arrangements of the isotope being "excited". This signature is used to diagnose certain metabolic disorders, especially those affecting the brain, as well as to provide information on tumor metabolism.
Magnetic resonance imaging was developed from knowledge gained in the study of nuclear
magnetic resonance. In its early years the technique was referred to as nuclear magnetic
resonance imaging (NMRI). However, as the word nuclear was associated with ionizing
radiation exposure it is generally now referred to simply as MRI. Scientists still
use the term NMRI when discussing non-