A method of performing a magnetic resonance imaging reference scan of a patient placed within an examination volume of a magnetic resonance imaging system having a main magnetic field strength and a set of detector elements, the method comprising: - applying a pulse sequence to the examination volume, said pulse sequence sequentially comprising a first low-flip angle radio frequency pulse (200, 300), a first frequency encoding gradient pulse (204, 302), a second low-flip angle radio frequency pulse (202, 301), a second frequency encoding gradient pulse (206, 302'), and a third frequency encoding gradient pulse (208, 210, 330') to the examination volume; - measuring using the set of detector elements a first gradient echo (214, 310) caused by the second low-flip angle radio frequency pulse (202, 301), the second frequency encoding gradient pulse, and the third frequency encoding gradient pulse; - measuring using the set of detector elements a second gradient echo (216, 312) caused by the first low-flip angle radio frequency pulse (200, 300), the first frequency encoding gradient pulse, and the third frequency encoding gradient pulse; wherein the difference TE2 - TE1 between the echo times of the first and second gradient echoes equals the inverted frequency difference between watery tissue and fat tissue at the main magnetic field strength, - determining a phase difference between the measured first and second gradient echoes for each image point of the examination volume; and - determining a local magnetic field inhomogeneity map for each image point of the examination volume using the phase difference, - determining an amplitude or a complex value of the first or second gradient echo measured using the set of detector elements; and - determining for each image point of the examination volume a coil sensitivity matrix of ratios of the amplitudes or complex values measured by the set of detector elements. - applying a pulse sequence to the examination volume, said pulse sequence sequentially comprising a first low-flip angle radio frequency pulse (200, 300), a first frequency encoding gradient pulse (204, 302), a second low-flip angle radio frequency pulse (202, 301), a second frequency encoding gradient pulse (206, 302'), and a third frequency encoding gradient pulse (208, 210, 330') to the examination volume; - measuring using the set of detector elements a first gradient echo (214, 310) caused by the second low-flip angle radio frequency pulse (202, 301), the second frequency encoding gradient pulse, and the third frequency encoding gradient pulse; - measuring using the set of detector elements a second gradient echo (216, 312) caused by the first low-flip angle radio frequency pulse (200, 300), the first frequency encoding gradient pulse, and the third frequency encoding gradient pulse; wherein the difference TE2 - TE1 between the echo times of the first and second gradient echoes equals the inverted frequency difference between watery tissue and fat tissue at the main magnetic field strength, - determining a phase difference between the measured first and second gradient echoes for each image point of the examination volume; and - determining a local magnetic field inhomogeneity map for each image point of the examination volume using the phase difference, - determining an amplitude or a complex value of the first or second gradient echo measured using the set of detector elements; and - determining for each image point of the examination volume a coil sensitivity matrix of ratios of the amplitudes or complex values measured by the set of detector elements.