Relaxometry

A nuclear magnetic resonance (NMR) apparatus, comprising:

• an acquisition logic configured to acquire a first series of MR images having a first scale and to acquire a second series of MR images having a second, different scale, the first series of MR images and the second series of MR images being acquired in response to NMR excitation of an item;
• a signal evolution logic configured to produce a combined signal evolution, where the combined signal evolution represents a first signal evolution associated with the relaxation of nuclei as identified in the first series of images and a second signal evolution associated with the relaxation of nuclei as identified in the second series of images;
• and
• a matching logic configured to compute a value for an NMR parameter for the item by comparing the combined signal evolution to a set of combined comparative signal evolutions.

A non-transitory computer-readable medium storing computer executable instructions that when executed by a computer control the computer to perform a method, the method comprising:

• controlling a nuclear magnetic resonance (NMR) apparatus to cause selected nuclei in an item to resonate by applying radio frequency (RF) energy to the item;
• controlling the NMR apparatus to produce a first series of magnetic resonance (MR) images of the item, the first series of MR images having a first scale;
• controlling the NMR apparatus to produce a second series of MR images of the object, the second series of MR images having a second, different scale;
• controlling the NMR apparatus to produce a combined signal evolution from a first signal evolution associated with the first series of MR images and a second signal evolution associated with the second series of MR images;
• and
• controlling the NMR apparatus to characterize relaxation of the selected nuclei in the item as a function of an orthogonal matching pursuit (OMP) that compares the combined signal evolution to a set of combined comparative signal evolutions.