Purpose: To create regional cerebral blood flow maps with contrast material-enhanced power Doppler ultrasound (US).
Materials and methods: In six anesthetized newborn piglets, cerebral hyperemia was induced after intrastriatal injection of 5 mumol of N-methyl-D-aspartic acid. Coronal power Doppler US was performed with a microbubble-based contrast agent, and cerebral blood flow was determined before and at 15, 30, and 60 minutes after injection. Images were digitized and analyzed for changes in mean pixel intensity. A bolus injection curve was constructed by plotting mean pixel intensity versus time, and the area under this normalized curve was compared with cerebral blood flow.
Results: Hemispheric cerebral blood flow increased from 40 mL/min/100 g +/- 1 (mean +/- standard error) to 90 +/- 12, 86 +/- 8, and 85 +/- 12 at 15, 30, and 60 minutes after injection, respectively (P < .0001 [analysis of variance]). Hemispheric mean pixel intensity at peak contrast also increased from 69 units +/- 5 to 120 +/- 4, 112 +/- 6, and 98 +/- 13 at 15, 30, and 60 minutes after injection, respectively (P < .003). The area under the normalized curve correlated well with changes in hemispheric and striatal cerebral blood flow (r = .73, P = .0001; r = .62, P = .0001, respectively).
Conclusion: In the newborn brain, regional blood flow maps can be created accurately with contrast-enhanced power Doppler US.