The invention relates to a method of MR imaging of at least a portion of a body (110) of a patient placed in an examination volume of a MR device, the method comprising the steps of:—subjecting the portion of the body (110) to an imaging sequence comprising at least one RF pulse, the RF pulse being transmitted toward the portion of the body (110) via a RF coil arrangement (109) to which RF signals are supplied by two or more RF power amplifiers the RF power amplifiers being activated alternately during the imaging sequence in a time-multiplexed fashion, wherein the imaging sequence requires a RF duty cycle and/or a RF pulse duration exceeding the specification of at least one of the RF power amplifiers;—acquiring MR signals from the portion of the body (110); and—reconstructing a MR image from the acquired MR signals. Moreover, the invention relates to a method of MR spectroscopy involving the alternating use of RF power amplifiers in a time-multiplexed fashion.