Diagnostic ultrasound ( PDFDrive )

1734 PART V Pediatric Sonography
A
B
C
FIG. 51.4 Peripheral Borders of Segments:
Hepatic Veins. (A) Dissected specimen shows
the left, middle, and right hepatic veins (L, M,
R). The position of the segments is indicated
by numbers. (B) and (C) Subxiphoid, oblique
sonogram at a similar plane as in (A) shows
the three hepatic veins. (With permission from
Bismuth H. Surgical anatomy and anatomical
surgery of the liver. World J Surg. 1982;6[1]:
3-9. 1 )
8; and the right hepatic vein separates segments 5 and 8 from
segments 6 and 7. With the oblique subxiphoid view, the right
portal vein is seen en face, which helps separate the supericial
segment 5 from the more deeply situated segment 8.
he sonographic examination of the child’s liver should include
visualization of the right and let portal veins and their segmental
branches, as well as the hepatic veins. Not only can focal lesions
be identiied and accurately localized, but thrombosis, compression,
or tumor invasion of vessels can be outlined. Doppler
sonography is added when the presence and direction of blood
low within these veins need to be assessed. Exploring the liver
through its vessels is an excellent way to ensure that the sonographic
examination is complete and not just an arbitrary glance
at this otherwise homogeneous organ with variable contours
and few landmarks except for its veins. Because the branches of
the hepatic artery and the bile ducts are neighbors of the portal
veins, the examination of the lobar and segmental portal veins
ensures a complete assessment of these structures as well.
NEONATAL JAUNDICE
he cause of persistent jaundice in the newborn is oten diicult
to deine because clinical and laboratory features may be similar
in hepatocellular and obstructive jaundice. If bile obstruction,
biliary atresia, or metabolic diseases such as galactosemia
and tyrosinemia are to be treated efectively with surgery or
speciic diet and medication, the diagnosis must be made early,
in the irst 2 to 3 months, before irreversible cirrhosis has
occurred.
Sonography plays an important role in deining causes of
extrahepatic obstruction to bile low that may be efectively
treated with early surgery, including choledochal cyst, biliary
atresia, and spontaneous perforation of the bile ducts. (Other
causes of bile duct obstruction, such as cholelithiasis, tumors of
the bile ducts or pancreas, and congenital stenosis of the common
bile duct (CBD), usually appear later in childhood.) Intrahepatic
causes of neonatal jaundice include hepatitis (bacterial, viral,
or parasitic) and metabolic diseases (e.g., galactosemia, tyrosinemia,
fructose intolerance, α 1 -antitrypsin deiciency, cystic
ibrosis, paucity of interlobular bile ducts, North American Indian
cirrhosis). Systemic diseases that cause cholestasis include heart
failure, shock, sepsis, neonatal lupus, histiocytosis, and severe
hemolytic disease.
he infant with jaundice is usually screened with sonography.
When dilation of the bile ducts is found, percutaneous cholangiography
or cholecystography may be performed if the cause