(B) Also called magnetic flux density with the SI unit tesla (T) usually denoted by the symbol B. The magnetic induction is the net magnetic effect from an externally applied magnetic field and the resulting magnetization.
The symbol H was used for the magnetic field (measured in amperes per meter (A/m)). However, this distinction is often ignored, and both quantities are often referred to as the magnetic field.
B is proportional to H (B = μH).
(μ is the magnetic permeability (in henries per meter) of the medium)

[B₀] A conventional symbol for the main magnetic field strength (magnetic flux density or induction) in a MRI system. Although historically used, H0 (units of magnetic field strength, ampere//meter) should be distinguished from the more appropriate B0 [units of magnetic induction, tesla].
In current MR systems it has a constant value over time varying from 0.02 to 4 T. Field strengths of 0.5 T and above are generated with superconductive magnets. High field strengths have a better signal to noise ratio (SNR). The optimal imaging field strength for clinical imaging is between 0.5 and 2.0 T.

See also the related poll result: 'In 2010 your scanner will probably work with a field strength of'

The interaction of the patient with the RF coil, which causes shifts of the resonance frequency and damping of the coil's resonance and hence reduction of the quality factor because of magnetic induction and dielectric losses in the patient.
The design and construction of a MRI coil is determined by the load on the coil. The load is either a phantom or the actual sample being imaged.

See also Radio Frequency Coil.

(B) See Magnetic Induction.

(H) The region surrounding a magnet (or current carrying conductor) is equipped with certain properties like that a small magnet in such a region experiences a torque that tends to align it in a given direction. Magnetic field is a vector quantity; the direction of the field is defined as the direction that the north pole of the small magnet points when in equilibrium.

A magnetic field produces a magnetizing force on a body within it. Although the dangers of large magnetic fields are largely hypothetical, this is an area of potential concern for safety limits. Formally, the forces experienced by moving charged particles, current carrying wires, and small magnets in the vicinity of magnet are due to magnetic induction (B), which includes the effect of magnetization, while the magnetic field (H) is defined so as not to include magnetization. However, both B and H are often loosely used to denote magnetic fields.