Figure 5

Perfusion ULM imaging is more robust to shorter acquisition times than vascular flow. ULM images depicting increased image fidelity with increasing amounts of input data (5–20 s) are displayed for both tissue perfusion (a–c) and vascular flow components (d–f). Representative axial images of the cervical spinal cord, with a hypoperfused region due to a moderate unilateral contusion injury, are depicted. Images are scaled from 0 to 30 detected bubbles. The saturation rate is plotted for a representative example in (g). Saturation percent is defined as the number of pixels within the spinal cord filled with a given amount of input data versus the total number of perfused pixels in the spinal cord (e.g., only those pixels which are nonzero after \(\sim\)40 total seconds total acquisition time). The perfusion image reaches 90% saturation 16.2 s faster than the flow image (9.0 vs. 25.2 s). (h-j) Zoomed examples of progressive filling of the microcirculation in penumbral tissue adjacent to the contusion and recovery of smaller branching vessels (k–m) with additional input data are shown.