Ultrasound changes within the liver after total pancreatectomy and intrahepatic islet cell autotransplantation

Intrahepatic infusion is the most common method of islet autotransplantation. Structural and functional changes within the liver may result from a number of factors, including embolization of the terminal branches of the portal vein, the effects of high insulin concentration on surrounding hepatocytes or responses to the death of admixed exocrine tissue. Awareness of the potential changes in the appearance of the liver on ultrasonography (USS), together with an assessment of liver function, is important in the postoperative surveillance of these patients.

We retrospectively reviewed 83 patients who underwent total pancreatectomy between 1993 and 2006. Thirty-three patients had total pancreatectomy alone (control group) and 50 patients underwent total pancreatectomy and islet autotransplantation (islet group). The islets were infused into the left lobe of the liver through the middle colic or recannalated umbilical vein. All patients underwent USS as part of their hepaticojejunostomy surveillance (initially every 6 months and then yearly).

"Echogenic nodularity" of the liver was observed in 25% of the islet group of patients and in none of the control group patients (P=0.03). These USS changes occurred from 6 to 12 months after islet autotransplantation and were not associated with any significant loss of liver function or increase in insulin requirements. The islet group had significantly less insulin requirement compared with the control group (P<0.01).

Echogenicity with a nodular appearance is a common ultrasonographic finding in the liver after intrahepatic islet autotransplantation. These changes do not seem to adversely affect liver function or insulin requirement. Appreciating these changes is important to avoid misinterpretation or over-interpretation of postoperative USS images.