Tissue-specific US contrast agent for evaluation of hepatic and splenic parenchyma.
OBJECTIVE
To evaluate the recently developed ultrasonographic (US) contrast agent SHU 563A, which is specifically taken up by the reticuloendothelial system (RES).


METHODS
Color Doppler imaging (CDI) was performed in a gel phantom, with SHU 563A microbubbles in stationary suspension. CDI was performed in vivo in five woodchucks with natural hepatomas and in 12 rabbits before and after intravenous bolus injections of SHU 563A (0.16-0.48 mL/kg). After a 15-135-minute delay, the liver and spleen were scanned again, and the image findings were compared with pathologic analysis results.


RESULTS
Phantom CDI demonstrated a random mosaic color pattern in spite of the lack of flow. This phenomenon, which is associated with bubble rupture, is termed induced acoustic emission. In vivo, delayed imaging demonstrated acoustic emission signals in normal parenchyma, whereas no mosaic color was seen in regions lacking reticuloendothelial cells (e.g., tumors). Four of 12 VX-2 tumors detected with pathologic analysis were detected with US alone; the remaining eight tumors were detected by using US with contrast agent (100%, P = .0078). Nine of 20 hepatomas were detected at baseline US, whereas 17 were detected after administration of SHU 563A (P = .0215). Acoustic emission enabled detection of hepatic tumors as small as 3 mm in diameter.


CONCLUSIONS
CDI with SHU 563A demonstrates a random mosaic color pattern, even without flow. The characteristic appearance of acoustic emission signals provides a distinctive method of visualizing normal hepatic tissues and substantially improves the detectability of hepatic tumors.
Forsberg
F
F
Department of Radiology, Thomas Jefferson University, Philadelphia, PA 19107, USA.
Goldberg
B B
BB
Liu
J B
JB
Merton
D A
DA
Rawool
N M
NM
Shi
W T
WT
D000818:Animals; D006528:Carcinoma, Hepatocellular / Q000000981:diagnostic imaging / Q000662:veterinary; D003287:Contrast Media; D004659:Enbucrilate; D008099:Liver / Q000000981:diagnostic imaging*; D008113:Liver Neoplasms / Q000000981:diagnostic imaging / Q000662:veterinary; D008114:Liver Neoplasms, Experimental / Q000000981:diagnostic imaging; D008392:Marmota; D019047:Phantoms, Imaging; D011108:Polymers; D011817:Rabbits; D012680:Sensitivity and Specificity; D013154:Spleen / Q000000981:diagnostic imaging*; D018615:Ultrasonography, Doppler, Color
D003287:Contrast Media; D011108:Polymers; C105825:SH U 563 A; D004659:Enbucrilate