A medical imaging system, comprising: a timing optimization unit configured to select i) a first echo time corresponding to an echo time of a free induction decay measured with a UTE pulse sequence and a second echo time of a modified Dixon, mDixon, pulse sequence and ii) a sufficient number of repetition times to generate a magnetic resonance, MR, image of an imaged subject of at least a first resolution, with the phase angle difference between water and fat at the second echo time being unequal to 0° and 180° thereby resulting in the selection of a UTE-mDixon pulse sequence; a magnetic resonance, MR, scanner configured to apply the selected UTE-mDixon pulse sequence to the subject and to receive MR data from the subject, the MR scanner comprising i) a gradient control configured to control application of one or more gradient magnetic fields to produce a first and a second echo at the first and the second echo time and ii) one or more gradient coils configured to apply a gradient field to the subject; an MR reconstruction unit configured to reconstruct the at least one MR image based on the MR data; an MR classification unit configured to segment and/or classify tissues based on the reconstructed at least one MR image; an attenuation map unit configured to construct the attenuation map based on the segmented and/or classified tissues of the at least one MR image; and a nuclear imaging system configured to receive nuclear decay data and to generate at least one nuclear image of the first resolution based on the received nuclear decay data from an imaged subject and the attenuation map, wherein the generating of the nuclear image includes registering the attenuation map to the received nuclear decay data, wherein the phase angle difference between water and fat at the second echo time is in the range of 150° +/- 10°. a timing optimization unit configured to select i) a first echo time corresponding to an echo time of a free induction decay measured with a UTE pulse sequence and a second echo time of a modified Dixon, mDixon, pulse sequence and ii) a sufficient number of repetition times to generate a magnetic resonance, MR, image of an imaged subject of at least a first resolution, with the phase angle difference between water and fat at the second echo time being unequal to 0° and 180° thereby resulting in the selection of a UTE-mDixon pulse sequence; a magnetic resonance, MR, scanner configured to apply the selected UTE-mDixon pulse sequence to the subject and to receive MR data from the subject, the MR scanner comprising i) a gradient control configured to control application of one or more gradient magnetic fields to produce a first and a second echo at the first and the second echo time and ii) one or more gradient coils configured to apply a gradient field to the subject; an MR reconstruction unit configured to reconstruct the at least one MR image based on the MR data; an MR classification unit configured to segment and/or classify tissues based on the reconstructed at least one MR image; an attenuation map unit configured to construct the attenuation map based on the segmented and/or classified tissues of the at least one MR image; and a nuclear imaging system configured to receive nuclear decay data and to generate at least one nuclear image of the first resolution based on the received nuclear decay data from an imaged subject and the attenuation map, wherein the generating of the nuclear image includes registering the attenuation map to the received nuclear decay data,