Magnetic resonance imaging device and method for calculating oxygen extraction fractions

A method of calculating an oxygen extraction fraction in a test subject by using measurement data acquired by imaging through an MRI apparatus, comprising,

• reconstructing an image from a complex image of the test subject by using the measurement data,
• calculating a susceptibility distribution by using the complex image,
• separating the susceptibility distribution into tissue-specific susceptibility distributions of a plurality of tissues to obtain separated tissue images, and
• estimating the oxygen extraction fraction in the test subject from the tissue-specific susceptibility distributions, as to at least one of the separated tissue images, under the assumption that a magnetic susceptibility of any pixel is equal to the magnetic susceptibility in an area having a predetermined size surrounding the pixel.

A method of calculating an oxygen extraction fraction in a test subject by using measurement data acquired by imaging through an MRI apparatus, comprising,

• reconstructing a plurality of complex images at different echo times by using the measurement data,
• calculating a distribution of an apparent transverse relaxation rate R2* or a distribution of a difference between the apparent transverse relaxation rate R2* and a transverse relaxation rate R2,
• separating the distribution of the apparent transverse relaxation rate R2* or the distribution of the difference, into tissue-specific separated images of a plurality of tissues, and
• estimating the oxygen extraction fraction in the test subject, from the distribution of the apparent transverse relaxation rate R2* or the distribution of the difference, as to at least one of the separated tissue images, under the assumption that a value of any selected pixel is equal to pixel values in an area having a predetermined size surrounding the selected pixel.