The smallest distance between two points in the object that can be distinguished as separate details in the image, generally indicated as a length or a number of black and white line pairs per mm (lp/mm).
The specific criterion for
resolution to be used, depends on the type of test used (e.g., bar pattern or contrast-detail
phantom).
As the ability to separate or detect objects depends on their
contrast and the
noise, and the different MR parameters of objects will affect image
contrast differently for different imaging techniques, care must be taken in comparing the results of
resolution phantom tests of different machines and no single simple measure of
resolution can be specified.
The
resolution may be an
isotropic one. The
resolution may be larger than the size corresponding to the discrete image
element (
pixel), although it cannot be smaller.