Magnetic resonance microscopy

The authors describe and demonstrate what they prefer to call "high resolution Magnetic Resonance Imaging" (MRI). Provided that the sample contains a reasonable quantity of "mobile" protons, MRI can be achieved in 2 or 3 dimensions for objects up to the size of man. Commercially available magnets for such measurements fall into 3 main categories. The first are magnets up to 9 cm room temperature bore which operate at magnetic field strengths of 2-14 Tesla. They can be used to study objects up to 2 cm in diameter with spatial resolution in the range 20-50 microns; as indicated earlier higher resolution for smaller samples can be achieved under special conditions. The second category of magnets have a room temperature bore of 30-40 cm and are available at field strengths of 0.5 to 5 Tesla; magnets of 20 cm diameter are available at fields up to 10 Tesla. Magnets of 30 cm diameter have a field of view of 8-10 cm with spatial resolution achievable in the range 70-100 microns. Finally magnets with a room temperature bore in the range 75-100 cm diameter are suitable for objects up to the size of man; the in-plane resolution which they can produce is in the range of sub-millimetre for slice thickness in the range 2-10 mm