Diagnostic ultrasound ( PDFDrive )

CHAPTER 18 Organ Transplantation 639
A
B
C
D
FIG. 18.16 Portal Vein: Bland Thrombus in Two Patients. Patient 1: (A) Transverse sonogram and (B) corresponding contrast-enhanced CT
show nonocclusive thrombus in the main portal vein (arrows). Patient 2: (C) Transverse sonogram and (D) corresponding contrast-enhanced CT
scan show nonocclusive thrombus in the ascending ramus of the left portal vein (arrows).
irregular walls and particulate internal luid, with or without
associated septations.
Both infarcts and abscesses may contain bubbles of air, visualized
as bright echogenic foci with or without posterior acoustic
shadowing (Fig. 18.25). Occasionally, bubbles of air within the
lumen of an intraparenchymal abscess can be confused with
benign pneumobilia or may be mistaken for air outside the liver
within the gastrointestinal tract. A high index of suspicion is
critical in patients at risk for either abscess or infarct to avoid
these misinterpretations.
Intrahepatic Solid Masses
he diferential diagnosis of a solitary mass in the transplanted
liver is similar to that in the native liver. For example, benign
lesions, such as hemangiomas and cysts, are relatively common
in the transplanted liver, with the same range of appearances as
described for the native liver. However, several pathologies unique
to the transplanted liver may also appear as a solid or complex
mass on gray-scale ultrasound, including infarcts (Fig. 18.26),
abscesses, hematomas, recurrent or metastatic HCC, and posttransplant
lymphoproliferative disorder (PTLD).
Recurrent hepatocellular carcinoma is a serious complication
that can potentially develop ater transplantation in patients with
a preoperative history of end-stage cirrhosis with known or occult
hepatomas. he most common site of recurrent HCC is the lung,
presumably caused by embolization with tumor cells through
the hepatic veins before or during transplantation. he second
most common location of recurrent hepatomas is within the
allograt, followed by regional or distant lymph nodes. Early
detection of recurrent hepatomas in the transplanted liver is