Use of specific relaxation agents for organs or pathologies for modifying the contrasts in medical imaging by nuclear magnetic resonance

Claim 1

A diagnostic process consisting of examining certain organs by nuclear magnetic resonance, which comprises: (a) introducing into the organism of a patient to be examined a contrast-modifying, non-toxic dosage amount of a relaxation agent consisting of a complex of a paramagnetic element selected from the group consisting of lanthanides and transition metals having atomic numbers 21 to 29, 42 and 44, and a biologically active ligand or a ligand coupled to a biologically active molecule specific of an organ or a pathology, and said liquid being selected from the group consisting of: macrocyclic diaza compounds of formula: ##STR32## in which t 1 and t 2 , which can be the same or different, are numbers between 0 and 2 and in which the groups R 31 and R 32 , which can be the same or different, represent a hydrogen atom, (CH 2 ) n --COOR 8 , with R 8 representing a hydrogen atom or a physiologically acceptable metal, (CH 2 ) n SH, (CH 2 ) n OH, ##STR33## with R 9 and R 10 , which can be the same or different, representing a hydrogen atom or a C 1 to C 4 alkyl radical and n being an integer between 1 and 4, or in which R 31 and R 32 can together form the radical --CH 2 --CH 2 --O--(CH 2 --CH 2 --O)t 3 --CH 2 --CH 2 --with t 3 number between 0 and 2, the different carbon atoms of the diaza compound also being substitutable by one or more radicals chosen from among (CH 2 ) n -COOR 8 , (CH 2 ) n -SH, (CH 2 ) n OH, ##STR34## with R 9 and R 10 , which can be the same or different, representing a hydrogen atom or a C 1 to C 4 alkyl radical and n being a number between and 1 and 4; and (b) producing an image of the organ or organs to be examined by nuclear magnetic resonance.