Patent ID: 8784778

Claim:
A method for the in vivo determination, by use of the MRI technique, of the value of a physical or chemical parameter of diagnostic interest selected from the group consisting of temperature, pH, partial pressure of oxygen or carbon dioxide, specific ion or metabolite concentration and specific enzymatic activity in a human or animal body organ, fluid or tissue, said method comprising: administering to said human or animal a diagnostically effective amount of a slow tumbling paramagnetic agent that is a nano-sized system comprising a liposome entrapping HPDO3A complexed with a paramagnetic metal in an inner aqueous phase at a minimum concentration of 5 mM, and having a mean diameter ≧5 nm; recording a MRI image; calculating the R 2p /R 1p ratio, which acts as a reporter of a change in the parameter of interest; and determining the value of the parameter of interest through the obtained R 2p /R 1p ratio.