For T1ρ quantification, a three-dimensional (3D) acquisition is desired to obtain high-resolution images. In order to achieve a rapid and robust acquisition of 3D T1 rho mapping data, we examined here the 3D sub-millimeter isotropic resolution sequences, applying them to the assessment of knee-joint. 3D isotropic resolution sequences can reduce partial-volume artifacts through the acquisition of thin continuous sections through joints. Furthermore, the isotropic source data can be used to create multiplanar reformations (MPRs). With the optimized voxel size (0.8mm3), we could obtain motion-robust high-quality isotropic images within the time constraints of a clinical exam (<10 minutes) .