[en] We propose a fast 3-dimensional (3D) B₁ mapping method using 3D FLASH (fast low angle shot) with preparation pulses. We optimized scan parameters using a simulation of spin relaxation to achieve the shortest acquisition time while maintaining the accuracy of the B₁ map and then applied the method to phantom imaging using a 3-tesla scanner and compared the results with those using DAM (double angle method) to evaluate accuracy. Although there was a slight offset in the B₁ value, the distribution of the B₁ map was similar between the proposed method and DAM. Acquisition time was 18.3 s for the proposed method and 160 s for DAM. We demonstrated that the proposed method provides fast 3D B₁ mapping with equivalent accuracy to that of DAM. (author)

[en] Using 4 and 8-channel super-parallel magnetic resonance (MR) microscopes with a horizontal bore 2.34T superconducting magnet developed for 3-dimensional MR microscopy of the large Kyoto Collection of Human Embryos, we acquired T₁-weighted 3D images of 1204 embryos at a spatial resolution of (40 μm)³ to (150 μm)³ in about 2 years. Similarity of image contrast between the T₁-weighted images and stained anatomical sections indicated that T₁-weighted 3D images could be used for an anatomical 3D image database for human embryology. (author)