This communication describes radiofrequency pulses capable of performing spatially periodic excitation, inversion, and refocusing. The generation of such pulses either by multiplication of existing radiofrequency pulses by a Dirac comb function or by means of Fourier series expansion is described. Practical schemes for the implementation of such pulses are given, and strategies for optimizing the pulse profile at fixed pulse duration are outlined. The pulses are implemented using a spin‐echo sequence. The power deposition is independent of the number of slices acquired, and hence the power deposition per slice is considerably reduced compared to multislice imaging. Excellent image quality is obtained both in phantoms and in images of the human head. These pulses should find widespread application for multiplexed imaging, in particular at high static magnetic field strengths and for pulse sequences that have a high radiofrequency power deposition and could lead to dramatic increases in scanning efficiency. Magn Reson Med, 2011. © 2011 Wiley Periodicals, Inc.

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Magnetic resonance fingerprinting (MRF) is a general framework to quantify multiple MR‐sensitive tissue properties with a single acquisition. There have been numerous advances in MRF in the years since its inception. In this work we highlight some of the recent technical developments in MRF, focusing on sequence optimization, modifications for reconstruction and pattern matching, new methods for partial volume analysis, and applications of machine and deep learning. Level of Evidence: 2 Technical Efficacy: Stage 2 J. Magn. Reson. Imaging 2020;51:993–1007.