Nitroxide NMR contrast enhancing agents and their use in NMR imaging

Claim 1

A method of enhancing the image obtained by NMR scanning of an organ associated with the cardiovascular system of a human being which comprises injecting into the blood of the human being, prior to the NMR scan on the organ, in admixture with a non-toxic injectable pharmacologically acceptable aqueous vehicle, an amount which is both nontoxic and effective to reduce the relaxation time of the blood during the scanning period sufficiently to enhance the NMR image produced by the scan of a charged, stable organic nitroxide of the formula: ##STR8## wherein R 1 , and R 4 each are alkyl or hydroxyalkyl of 1-4 carbon atoms; R 2 and R 3 each are alkyl, hydroxyalkyl of 1-4 carbons or --alk--R', in which alk is alkylene of 1-8 carbon atoms and R' is R as defined below, --NH 2 , --NHR 1 , or --NR 1 R 2 , in which R 1 and R 2 are alkyl or hydroxyalkyl of 1-4 carbon atoms; and R is --alk--COO - M + or --B--N + (Alk) 3 Hal in which alk is as defined above, B is a divalent bond or alk as defined above and M + is an ammonium or metal ion, Alk is alkyl of 1-8 carbon atoms or a corresponding alkyl group substituted by a free or esterified hydroxy group, and Hal - is Cl - , Br - or I - .

Claim 2

A method of enhancing the image obtained by NMR scanning of an organ associated with the cardiovascular system of a human being which comprises injecting into the blood of the human being, prior to the NMR scan on the organ, in admixture with a non-toxic injectable pharmacologically acceptable aqueous vehicle, an amount which is both nontoxic and effective to reduce the relaxation time of the blood during the scanning period sufficiently to enhance the NMR image produced by the scan of a charged, stable organic nitroxide of the formula: ##STR8## wherein R 1 , and R 4 each are alkyl or hydroxyalkyl of 1-4 carbon atoms; R 2 and R 3 each are alkyl, hydroxyalkyl of 1-4 carbons or --alk--R', in which alk is alkylene of 1-8 carbon atoms and R' is R as defined below, --NH 2 , --NHR 1 , or --NR 1 R 2 , in which R 1 and R 2 are alkyl or hydroxyalkyl of 1-4 carbon atoms; and R is --alk--COO - M + or --B--N + (Alk) 3 Hal in which alk is as defined above, B is a divalent bond or alk as defined above and M + is an ammonium or metal ion, Alk is alkyl of 1-8 carbon atoms or a corresponding alkyl group substituted by a free or esterified hydroxy group, and Hal - is Cl - , Br - or I - .

Claim 11

A method of enhancing the image obtained by NMR scanning of the joint of an animal which comprises injecting into the joint of the animal, prior to the NMR scan on the joint, in admixture with a non-toxic injectable pharmacologically acceptable aqueous vehicle, an amount which is both non-toxic and effective to enhance the NMR image produced by the scan of a neurologically acceptable and nontoxic charged, stable organic nitroxide of the formula: ##STR9## wherein R 1 , and R 4 each are alkyl or hydroxyalkyl of 1-4 carbon atoms; R 2 and R 3 each are alkyl, hydroxyalkyl of 1-4 carbons or --alk--R', in which alk is alkylene of 1-8 carbon atoms and R' is R as defined below, --NH 2 , --NHR 1 , or --NR 1 R 2 , in which R 1 and R 2 each are alkyl or hydroxyalkyl of 1-4 carbon atoms; and R is --alk--COO - M + or --B--N + (Alk) 3 Hal - in which alk is as defined above, B is a divalent bond or alk as defined above and M + is an ammonium or metal ion, Alk is alkyl of 1-8 carbon atoms or a corresponding alkyl group substituted by a free or esterified hydroxy group, and Hal - is Cl - , Br - or I - .

Claim 12

A method of enhancing the image obtained by NMR scanning of the joint of an animal which comprises injecting into the joint of the animal, prior to the NMR scan on the joint, in admixture with a non-toxic injectable pharmacologically acceptable aqueous vehicle, an amount which is both non-toxic and effective to enhance the NMR image produced by the scan of a neurologically acceptable and nontoxic charged, stable organic nitroxide of the formula: ##STR9## wherein R 1 , and R 4 each are alkyl or hydroxyalkyl of 1-4 carbon atoms; R 2 and R 3 each are alkyl, hydroxyalkyl of 1-4 carbons or --alk--R', in which alk is alkylene of 1-8 carbon atoms and R' is R as defined below, --NH 2 , --NHR 1 , or --NR 1 R 2 , in which R 1 and R 2 each are alkyl or hydroxyalkyl of 1-4 carbon atoms; and R is --alk--COO - M + or --B--N + (Alk) 3 Hal - in which alk is as defined above, B is a divalent bond or alk as defined above and M + is an ammonium or metal ion, Alk is alkyl of 1-8 carbon atoms or a corresponding alkyl group substituted by a free or esterified hydroxy group, and Hal - is Cl - , Br - or I - .