Figure E.1:

Illustration of the optimization-based reconstruction for one example arterial signal time-course. Panel (a) shows the ground truth signal (blue curve) and the time-course with temporal resolution of 3.5 s reconstructed by the conventional inverse Fourier transform (“IFFT Recon”; pink circle and dash line). The whole time-course is truncated, and a 10 s interval is selected (red dash lines and arrow). Panel (b) shows the signal (“Opti-based Recon”; red-cyan dots and lines) reconstructed by the optimization-based algorithm within the selected interval. Specifically, the red dots are preserved while cyan ones are eliminated to avoid extrapolative errors. In panels (c) and (d), reconstructions of the whole time-course with temporal resolutions of 2.5 s and 0.5 s, respectively, is achieved by shifting selected intervals.