Renal cortical perfusion in rabbits: visualization with color amplitude imaging and an experimental microbubble-based US contrast agent.
OBJECTIVE
To evaluate an experimental microbubble-based ultrasound (US) contrast agent (Imagent US, formulation AF0150) in the kidney to help identify focal perfusion abnormalities.


METHODS
Six incremental doses (0.007-0.2 mL/kg) of contrast material were injected intravenously in six New Zealand rabbits (3.1-3.5 kg), with experimental focal renal ischemia in five kidneys. Unenhanced and contrast material-enhanced color amplitude and gray-scale images of the kidney were analyzed for changes in mean pixel intensity. Kidneys were harvested and examined pathologically.


RESULTS
On contrast-enhanced color amplitude images, mean pixel intensity increased significantly in cortex and medulla at every dose level (P < .0005) (with doses as low as 0.007 mL/kg), and differences were significant in cortical peak intensity and duration of enhancement with incremental increases in dose (P < .006). On contrast-enhanced gray-scale images, renal cortical enhancement reached statistical significance only at the highest dose (0.2 mL/kg). Duration of gray-scale tissue enhancement was not dose related. Color mean pixel intensity markedly increased in areas of normally perfused kidney (P = .002) but remained essentially unchanged in ischemic areas (P = .34).


CONCLUSIONS
Color Doppler and gray-scale images enhanced with this microbubble-based US contrast agent depict renal cortical perfusion clearly in rabbits.
Taylor
G A
GA
Department of Radiology, Harvard Medical School, Boston, MA, USA.
Ecklund
K
K
Dunning
P S
PS
D000818:Animals; D003287:Contrast Media; D005466:Fluorocarbons; D007511:Ischemia / Q000000981:diagnostic imaging*; D007672:Kidney Cortex / Q000098:blood supply* / Q000000981:diagnostic imaging; D007679:Kidney Medulla / Q000098:blood supply / Q000000981:diagnostic imaging; D011817:Rabbits; D012079:Renal Circulation; D018615:Ultrasonography, Doppler, Color / Q000379:methods*
D003287:Contrast Media; D005466:Fluorocarbons; C099091:Imagent US