MRI image enhancement of bone and related tissue using complexes of paramagnetic cations and polyphosphonate ligands

A method of preferentially enhancing magnetic resonance image contrast, said method comprising administering to said patient an effective amount of a pharmaceutical agent comprising a physiologically compatible salt of the complex produced by the addition of a suitable paramagnetic metal cation to a chelator having the formula ##STR7## in which:

• the R.sup.11 moieties are each independently ##STR8## in which R.sup.14, R.sup.15 and R.sup.16 are independently selected from the group consisting of H and alkyl and aryl groups which do not interfere with complexation;
• R.sup.17 is selected from the group consisting of H, OH, NH.sub.2, and alkyl and aryl groups which do not interfere with complexation;
• and n is zero or 1;
• the R.sup.12 moieties are each independently selected from the group consisting of H and alkyl and aryl groups which do not interfere with complexation;
• the R.sup.13 moieties are each independently selected from the group consisting of H and alkyl and aryl groups which do not interfere with complexation;
• t is 2 or 3;
• u is 2 or 3;
• v is 2 or 3;
• and
• w is 1.

A method of preferentially enhancing magnetic resonance image contrast in bone tissue and other tissue of a patient bearing recognition features in common with bone tissue, said method comprising administering to said patient an effective amount of a pharmaceutical agent comprising a physiologically compatible salt of the complex produced by the addition of a suitable paramagnetic metal cation to a chelator having the formula ##STR9## in which:

• the R.sup.21 moieties are each independently ##STR10## in which R.sup.24, R.sup.25 and R.sup.26 are independently selected from the group consisting of H and alkyl and aryl groups which do not interfere with complexation;
• R.sup.27 is selected from the group consisting of H, OH, NH.sub.2, and alkyl and aryl groups which do not interfere with complexation;
• and x is zero or 1;
• the R.sup.22 moieties are each independently selected from the group consisting of H and alkyl and aryl groups which do not interfere with complexation;
• and
• the R.sup.23 moieties are each independently selected from the group consisting of H and alkyl and aryl groups which do not interfere with complexation.