Patent ID: 7917188
Filing Date: 2011-03-29
Classification: G01R

Abstract:
1. A method of providing a magnetic resonance (MR) image of at least a part of a body of an individual to whom an amount of a chemical exchange saturation transfer (CEST) contrast agent has been administered, the contrast agent having exchangeable entities including a measurable spin magnetic moment and forming at least one first exchangeable entity pool for exchanging the exchangeable entities with exchangeable entities of a main exchangeable entity pool naturally present in at least part of the body of the individual, the exchangeable entities of the main exchangeable entity pool having a measurable spin magnetic moment, the method comprising: defining a range of interest of a physico-chemical parameter between a first and a second parameter value, the physico-chemical parameter influencing an exchange rate of the exchangeable entities, irradiating the CEST contrast agent with pre-saturation RF pulses having a first pre-saturation frequency for saturating exchangeable entities of the first exchangeable entity pool, irradiating the CEST contrast agent with pre-saturation RF pulses having a second pre-saturation frequency for saturating exchangeable entities of the first exchangeable entity pool, the second pre-saturation frequency being different from the first pre-saturation frequency, for the first pre-saturation frequency, determining a first ratio of [(M for the second pre-saturation frequency, determining a second ratio of [(M determining a third ratio by dividing the first ratio by the second ratio to eliminate effect of concentration of the contrast agent on the MR image for forming an enhanced image; and displaying the enhanced image on a display, wherein the first and the second frequencies are selected such that they are both capable of at least partly pre-saturating the first exchangeable entity pool at least one value within the defined range of interest of the physico-chemical parameter, and wherein the first frequency and the second frequency are selected to have a different physico-chemical parameter dependence of changes due to the CEST.