Figure 5b. (a) Gray-scale sonogram of a PTA transplant reveals a heterogeneous appearance of the pancreatic parenchyma (arrows). Increased echogenicity of the pancreatic parenchyma renders the transplant isoechoic relative to the adjacent peripancreatic soft tissues. Because the pancreas lacks a defining capsule, the borders of the graft become indistinct, particularly in cases of acute graft rejection and pancreatitis. (b) Gray-scale sonogram of the pancreatic transplant in another patient demonstrates that sonographic delineation of the transplant is superior when it is outlined by fluid.