Diagnostic ultrasound ( PDFDrive )

678 PART II Abdominal and Pelvic Sonography
A B C
D
E
F
G
H
I
FIG. 18.63 Graft Thrombosis in Different Patients. (A) Transverse sonogram, (B) sagittal sonogram, and (C) color Doppler image show
nonocclusive venous thrombus (arrows). (D) Gray-scale ultrasound (arrow) and (E) correlative CT (arrows) show nonocclusive venous thrombus.
(F) Sagittal sonogram shows occlusive arterial thrombus (arrows). (G) Sagittal sonogram, (H) transverse sonogram, and (I) color Doppler image
show nonocclusive venous (arrowhead) and arterial (arrow) thrombus in the same transplant.
to local eddy currents, with a normal arterial waveform more
proximally.
Arteriovenous Fistula and Pseudoaneurysms
Arteriovenous istulas and pseudoaneurysms are rare complications
of pancreatic transplants and may be related to the blind
ligation of mesenteric vessels along the inferior border of the
pancreas during retrieval. In some patients, mycotic pseudoaneurysms
may occur in the setting of grat infection. 85
On gray-scale ultrasound, arterial malformations may not
be detectable. On color Doppler sonography, however, a mosaic
of intense colors may be identiied, produced by the tangle of
vessels within the malformation and adjacent tissue vibration.
Spectral Doppler ultrasound reveals high-velocity, low-resistance
low within the lesion, which is typical of arteriovenous shunting
(Fig. 18.65). On gray-scale ultrasound, pseudoaneurysms
usually appear as anechoic spherical structures, although
mural-based intraluminal thrombus may be detected. On
spectral Doppler ultrasound, the classic to-and-fro pattern may
be observed.
Rejection
Rejection is the most common cause of pancreatic grat loss
ater transplantation. his condition afects up to 40% of grats
and can be hyperacute, acute, or chronic. 77 Early recognition
of transplant rejection remains a challenge because clinical