Quantitative oxygen imaging systems and methods using echo-based single point imaging

A method of producing a high-resolution quantitative oxygen image of an in vivo sample comprising:

• providing at least two high-resolution 90°-τ-180° Hahn echo-based single point imaging (ESPI) images of the sample comprising:
• a first ESPI image comprising a reconstruction of a plurality of first EPR signals measured at a time Δt prior to a 180° refocusing pulse, and further comprises a plurality of logarithms of spatially-resolved first spin intensities, wherein each of the first spin intensities is mapped to one of a plurality of spatial positions within a sample image;
• and, a second ESPI image comprising a reconstruction of a plurality of second EPR signals measured at a time Δt after the refocusing pulse, and further comprises a plurality of logarithms of spatially-resolved second spin intensities, wherein each second spin intensity is mapped to one of the plurality of spatial positions within the sample image;
• determining for each one of the plurality of spatial positions within the sample image a spatially-resolved relaxivity between each of the plurality of logarithms of spatially-resolved spin intensities of the first ESPI image and each of the plurality of corresponding logarithms of spatially-resolved spin intensities of the second ESPI image;
• and determining for each one of the plurality of spatial positions within the sample a spatially-resolved oxygen content by interpolating a reference oxygen concentration from a predetermined table comprising a plurality of reference oxygen concentrations as a function of spatially-resolved relaxivities, and mapping each spatially-resolved oxygen content onto a corresponding spatial location within a sample image to produce the high-resolution quantitative oxygen image.

A system for producing a high-resolution quantitative oxygen image of an in vivo sample comprising:

• at least one processor;
• and, a plurality of modules executed on the at least one processor, the modules comprising:
• a 90°-τ-180° Hahn echo-based single point imaging (ESPI) image comparison module (1004) to derive a spatially-resolved relaxivity between each of a plurality of logarithms of spatially-resolved spin intensities of a first ESPI image and each of a plurality of logarithms of spatially-resolved spin intensities of a second ESPI image;
• and an oxygen imaging module (1006) to:
• determine a spatially-resolved oxygen concentration by interpolating a reference oxygen concentration from a predetermined table comprising a plurality of reference oxygen concentrations as a function of the spatially-resolved relaxivity, and mapping each spatially-resolved oxygen concentration onto a corresponding spatial location within a sample image to produce the high-resolution quantitative oxygen image.