Fig. 10.

Performance evaluation using retrospective undersampling of ungated perfusion MRI dataset: The ungated dataset was acquired without ECG gating and breath-holding as described in Section IV.A; A few frames of the original data, data recovered using CS with x-f sparsity penalty, and the DC-CS scheme are shown in the first four columns. The ungated acquisition enables us to acquire diastolic and systolic frames. However, the acceleration of this dataset is challenging due to the rapid cardiac motion (see high frequency ripples in x-t profile) and respiratory motion (see low frequency oscillations in x-t profile). The x-f space representation of the ground truth data depicts the modulation of the cardiac and contrast dynamics by the breathing motion at almost all the frequencies. The proposed DC-CS scheme corrects for the breathing motion, and exploits the sparsity of quasi-periodic dataset with cardiac and contrast dynamics (see the x-f profile of the motion corrected dataset in the last row). The residual ripples in the x-t profile of the deformation corrected dataset correspond to out of plane breathing motion. From the x-f, and x-t plots, it can be seen that DC-CS provides superior reconstructions over CS reconstructions (also see arrows in (b)).