Nuclear magnetic resonance methods and apparatus

摘要

A nuclear magnetic resonance method and apparatus for examining a predetermined particular location (55) in a body wherein processed data obtained from four procedures are combined to extract processed data relating to the particular location. Each procedure comprises exciting spins in a region (45) of the body including the location (55) and acquiring and processing data in respect of the excited spins. In a first procedure the excited spins are of the same phase throughout the region (45). In a second procedure the excited spins are of a first phase in a first portion (49) of the region (45) of which portion the predetermined location (55) forms part, and are of the opposite phase in the rest of the region (45). In a third procedure the excited spins are of a first phase in a second portion (53) of the region which intersects the first portion (45) at the predetermined location (55) and are of the opposite phase in the rest of the region (45). In a fourth procedure the excited spins are of a first phase in the first and second portions (49 and 53), excluding the predetermined location (55), and are of the opposite phase in the rest of the region (45). Adding the processed data signals from the first and fourth procedures and subtracting the processed data signals for the second and third procedures gives a resultant signal relating to the predetermined location (55) only.