Figure 1.

(A) High spatiotemporal resolution T₁-weighted DCE MRI was achieved using variable density, pseudo-random k-space sampling with a fully-sampled central “A” region, which consisted of 16% of the k-space views and was acquired in each k-space interval (red region), and a peripheral “B” region, one-third of which was acquired in each k-space interval (green, yellow, and blue regions). (B) Images for a single time frame were produced using data from a full k-space interval and the appropriate B sub-region data from the two preceding k-space intervals in order to create a fully-sampled k-space volume (backward view sharing). For example, images for a single, fully-sampled time frame (dark box) would be reconstructed using the A region and B sub-region acquired during one k-space interval (red and blue boxes within the dark box with lines leading to the MR image) and two B sub-regions from preceding k-space intervals (yellow and green boxes with lines leading to the MR image). The time required to collect all the data used for reconstruction of a single, fully-sampled time frame, including the data shared from neighboring k-space intervals, is called the temporal footprint, while the effective temporal resolution refers to the time between the acquisitions of the central region of k-space.