Figure 2.

Comparison of undersampled images in the time domain and in the low-dimensional, dictionary-derived subspace from an SMS cMRF acquisition with MB=3. (a) An image frame corresponding to TR #20 after demodulating the undersampled SMS k-space by the RF phase (for each slice) and gridding. The images contain severe aliasing artifacts due to the 3-fold slice acceleration and 48-fold in-plane acceleration. (b) Examples of coefficient images derived by projecting the undersampled images onto the low-dimensional subspace calculated from each slice’s dictionary. The first four coefficient images are displayed for each slice, which correspond to the four largest singular values.