Diagnostic ultrasound ( PDFDrive )

CHAPTER 4 The Liver 131
A
B
C
FIG. 4.65 Liver Trauma. (A) Acute intrahepatic bleed and
(B) acute perihepatic hematoma (arrows) between the liver surface
and the overlying abdominal wall show increased echogenicity.
(C) Older hematoma surrounds the tip of the right lobe of the
liver, appearing as a luid collection with strands.
common surgical shunts include mesocaval, distal splenorenal
(Warren shunts), mesoatrial, and portacaval. Duplex Doppler
sonography and color Doppler low imaging (CDFI) are reliable
noninvasive methods of assessing shunt patency or thrombosis. 218-221
Both modalities are efective in assessing portacaval, mesoatrial,
and mesocaval shunts. 218 Shunt patency is conirmed by demonstrating
low at the anastomotic site. If the anastomosis cannot
be visualized, hepatofugal portal low is an indirect sign of
patency. 219,220
Distal splenorenal communications are particularly diicult
to examine with duplex Doppler sonography because overlying
bowel gas and fat hinder accurate placement of the Doppler
cursor. 218,222 CDFI more readily locates the splenic and renal
limbs of Warren shunts. he splenic limb is best imaged from
a let subcostal approach, whereas the let renal vein is optimally
scanned through the let lank. Grant et al. 218 reported that color
Doppler sonography correctly inferred patency or thrombosis
in all 14 splenorenal communications by evaluating the low in
both limbs of the shunt.
Transjugular Intrahepatic Portosystemic Shunts
Transjugular intrahepatic portosystemic shunts (TIPS) are the
most popular technique for relief of symptomatic portal hypertension,
speciically varices with gastrointestinal bleeding, and less
oten, refractory ascites. Performed percutaneously with insertion
of an expandable metal stent, TIPS have less morbidity and
mortality than surgical shunt procedures. 223
he technique of performing TIPS requires transjugular access
to the infrahepatic IVC, with selection of the optimal hepatic
vein on the basis of its angle and diameter, most oten the right
hepatic vein. Ater targeting the portal vein with either luoroscopy
or Doppler sonography, a transjugular puncture needle is passed
from the hepatic vein to the intrahepatic portal vein and a shunt
created. he tract is dilated to an approximate diameter of 10 mm,