Science in Medicine - Magnetic Resonance Imaging - MRI

Magnetic Resonance Imaging (MRI) is primarily used to detect hydrogen containing molecules in the body.  Outside the medicinal field, MRI is commonly known as Nuclear Magnetic Resonance Imaging (NMR) as the method utilizes the spin of the protons (hydrogen nuclei) to detect them.  As water (H-O-H) contains protons, it is the soft tissue that gives the strongest signals and detected most efficiently while bone has fewer hydrogen atoms and gives a weak signal.
In this respect MRI complements CT.
As is true for other imaging methods also, the availability of fast computers has allowed these methods to be used as routine in hospitals and provide invaluable information about the human body - its functions and illnesses.
The physics of MRI is more complex than for other imaging techniques.  I have tried in my lecture to tone down the discussion for a non-specialist audience.  There are some detailed articles and good books available but seldom they are written for a nonscientific audience.  Hope this all makes sense: