Diagnostic ultrasound ( PDFDrive )

CHAPTER 18 Organ Transplantation 635
A
B
C
D
FIG. 18.12 Hepatic Artery Stenosis in Two Patients. Patient 1: (A) Intraparenchymal spectral Doppler ultrasound shows a low-resistance
waveform (resistive index [RI] = 0.4). (B) Corresponding contrast-enhanced CT angiogram shows subtle stenosis of the proximal hepatic artery
(arrow). Patient 2: (C) Intraparenchymal spectral Doppler shows a tardus-parvus, low-resistance waveform with a delayed acceleration time of
120 ms. (D) Corresponding CT angiogram shows long stenosis of the hepatic artery (between arrows).
artery and high-velocity jet across the celiac stenosis. Patients
are treated with division of the median arcuate ligament or, in
the case of atheromatous disease, an aortohepatic interposition
bypass grat 35,36 (Fig. 18.14).
Portal Vein Complications
Portal vein stenosis or thrombosis is uncommon, with a reported
incidence of 1% to 13%. 30,37,38 Risk factors include faulty surgical
technique, misalignment of vessels, excessive vessel length,
hypercoagulable states, and previous portal vein surgery. 30
Factors extrinsic to the portal vein may also contribute, such
as increased downstream resistance caused by a suprahepatic
stricture of the IVC or diminished portal venous blood low.
Clinical presentations include hepatic failure and signs of portal
hypertension (gastrointestinal hemorrhage from varices or
massive ascites).
Gray-scale ultrasound of portal vein stenosis may show
narrowing of the vessel lumen, usually at the anastomosis. Doppler
interrogation shows a focal region of color aliasing, relecting
turbulent, high-velocity low, with a threefold to fourfold velocity