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Fig 1. The basic principle of TSE180° and hyperTSE. A sketch of the radio-frequency (RF) of the refocusing pulses applying flip angles 
ref is shown with time in TSE180° (upper graph) and hyperTSE (lower graph). In TSE180°, a constant ref = 180° is used, whereas in hyperTSE, ref is varied along the echo train. The box indicates the echo written in the center of the k-space, which corresponds to the respective TE. Note that the hyperTSE uses a substantial later echo than the TSE180°. exec indicates excitation pulse.
