Fig. 1

Sequence diagram of the proposed flow encoded time-resolved 4D UTE acquisition indicating the temporal ordering of the flow encoding directions, readout and flow encoding gradient timing. The navigator location obtained from the center of k-space is indicated, as are the ADC delay, constant spoiler gradient in z-direction as well as the resulting 3D UTE center-out k-space encoding. To realize a cone-by-cone center-out UTE sampling; the readout gradient and dephaser strengths were modulated in the x, y and z directions according to [19], resulting in a 3D k-space encoding which starts in z-direction (blue color) and sampling cone by cone towards the negative z-direction (green color)