9%20ECOGRAFIA%20ABDOMINAL%20COMO%20CUANDO%20DONDE

THE PANCREAS 135
pancreatic juice into the abdominal cavity and
severe cases result in complete pancreatic transection
with pancreatic ascites.
The release of pancreatic enzymes triggers pancreatitis
and/or peritonitis, with the gland appearing
enlarged and hypoechoic.
Ultrasound may be helpful in localizing a collection,
but will not differentiate pancreatic secretions
from haematoma. CT is the method of
choice in cases of suspected pancreatic trauma,
although even here the signs of injury can be surprisingly
subtle considering the damage. 22
PANCREATIC TRANSPLANT
In patients with insulin-dependent diabetes mellitus
with end-stage renal disease, simultaneous pancreatic
and kidney transplant is a successful
treatment which improves the quality of life and
the survival of the patients. Typically such patients
also have severe complications, such as retinopathy
and vascular disease, which may be stabilized, or
even reversed, by transplantation.
Simultaneous pancreas and kidney transplantation
now has a 1-year graft survival of almost 90%
due to improved organ preservation techniques,
surgical techniques and immunosuppression. 23
The transplanted kidney is placed in the iliac
fossa with the pancreas on the contralateral side.
The donor kidney is transplanted in as usual, with
anastomoses to the recipient iliac artery and vein.
The pancreatic vessels are anastamosed to the contralateral
iliac vessels.
The pancreatic secretions are primarily by
enteric drainage, as the previous method of bladder
drainage was associated with an increased
incidence of urologic complications such as
urinary tract infection, haematuria or reflux
pancreatitis. 24
Postoperative monitoring of the pancreatic
transplant is difficult, on both clinical and imaging
grounds. No one imaging modality has proved
without limitations and a combination of ultrasound,
CT, MRI, angiography and nuclear
medicine may be required. 25 Postoperative complications
include thrombosis, infection, inflammation,
anastomotic leaks and rejection. Localized
postoperative bleeding usually resolves spontaneously.
Ultrasound appearances
The donor pancreas is usually situated in the iliac
fossa but can be placed more centrally, particularly
if a renal transplant has also been performed.
Ultrasound is limited in its ability to assess the
transplanted pancreas, even if it can be located
amongst the bowel loops. The lack of an adjacent
reference organ, such as the liver, makes assessment
of its echogenicity subjective, and therefore subtle
degrees of inflammation are difficult to detect.
Fluid collections are frequently concealed beneath
bowel and, when identified, their appearance is
non-specific. Contrast CT is more successful in
detecting anastomotic leaks and collections, and is
usually used for guided aspiration.
Colour Doppler should display perfusion
throughout the pancreas and the main vessels may
be traced to their anastomoses, depending on overlying
bowel (Fig. 5.10). Neither CT nor ultrasound
is particularly helpful in evaluating rejection,
and it is difficult to differentiate transplant pancreatitis
from true rejection. The Doppler resistance
index does not correlate with a rejection process
and has not been found useful. MRI has been
found to display more positive findings in pancreatic
rejection than other imaging modalities.
Figure 5.10 The transplanted pancreas may be difficult
to identify in the iliac fossa. The main artery is seen here
running through the body of the pancreas.