Systems and methods for producing pseudo-CT images using a dual flip angle multi-echo ultra-short echo time (DUFA-MUTE) MRI method are disclosed. The DUFA-MUTE MRI imaging method includes obtaining MR signals according to a DUFA-MUTE MRI sequence that includes first and second multiple ultrashort echo time (MUTE) sequence characterized by first and second flip angles FA1/FA2, and in which both MUTE sequences obtain MR signals at first and second echo times TE1/TE2. HU values are assigned to each imaged voxel based on each voxel's R1 value calculated from the MR signals, as well as each voxel's assigned tissue type. The imaged voxels and assigned HU values are combined to produce a pseudo-CT image. Pseudo-CT images optionally form the basis for attenuation maps suitable for use in combined PET/MRI systems and/or electron density maps suitable for use in radiation therapy systems.
