Diagnostic ultrasound ( PDFDrive )

668 PART II Abdominal and Pelvic Sonography
A B C
D E F
FIG. 18.52 Arteriovenous Malformation: Mimicker. (A)-(C) Sagittal sonograms show twinkling artifact produced by (A) lower-pole dystrophic
cortical calciication (arrow); (B) upper-pole stone; and (C) lower-pole stone. (D)-(F) Differentiation from AVM. On (D) color Doppler and (E)
power Doppler, color artifact (arrows) may be seen posterior to border of kidney. Size of twinkling artifact varies with size of the color box. (F) On
spectral Doppler ultrasound, the twinkling artifact shows linear bands as on these three spectral traces.
transplant in the setting of kidney transplants has been known
to improve long-term patient survival.
Surgical Technique
he simultaneous pancreas-kidney transplant is the most common
form of pancreas transplantation in the United States and accounts
of 80% of all pancreatic transplant procedures. To achieve
optimum functioning beta cell mass, the procedure is a wholeorgan
pancreas transplant performed in conjunction with a kidney
transplant. Best results are achieved if the procedure is performed
before the need for dialysis. his approach allows serum creatinine
to be used not only as a marker of renal rejection, but also as a
surrogate marker of pancreatic grat rejection. his is particularly
important because serum amylase and lipase are not sensitive
or speciic markers of pancreatic rejection. Serum amylase has
only 50% sensitivity for detection of rejection, and lipase may
be elevated in both rejection and pancreatitis. he ultimate
diagnosis of grat dysfunction is oten made on biopsy.
here are several further strategies for pancreas transplantation.
A pancreas transplant can be performed as a second step following
a successful renal transplant. he latter will typically be a living
donor kidney and is usually advised for diabetic patients younger
than age 5 with ongoing severe complications. he most severe
complication is hypoglycemic unawareness wherein a patient
may be wholly lacking the normal stigmata or warning signs of
a low glucose level (such as trembling, sweating, and tachycardia).
76 his is the second most common mode of pancreatic
transplant and contributes about 25% of all transplants in the
United States.
Finally, pancreas-only transplantation can be performed in
diabetic patients who have no evidence of diabetic nephropathy.
Only a minority of diabetic patients are eligible for this approach
because it is limited to patients whose hypoglycemic awareness
is challenging to manage medically.
here are two well-established techniques for pancreas
transplantation. Use of the bladder for exocrine drainage (duodenocystostomy)
and use of the iliac vessels for arterial and
venous supply were considered safer with regard to postoperative
infection. his more traditional surgery, exocrine bladder drainage,
involved anastomosing the donor duodenum to the urinary
bladder and the donor portal vein to the recipient external iliac
vein (systemic venous-endocrine drainage) 77 (Fig. 18.60). In this
circumstance the pancreas grat is placed in the right hemipelvis
and the renal grat on the let. he chronic loss of pancreatic
secretions into the bladder can result in problems with dehydration,
metabolic acidosis, and allograt pancreatitis. 3 here is also
a higher risk of chemical cystitis secondary to the high amylase
and lipase levels of pancreatic secretions. his can result in