Imaging of pancreas transplantation and its complications

Transplantation for type 1 diabetes: radiologist's primer on islet, pancreas and pancreas-kidney transplantation imaging

Whole-organ pancreas, pancreatic-kidney and islet transplantation are surgical therapeutic options for the treatment of type 1 diabetes. They can enable effective glycemic control, improve quality of life and delay/reduce the secondary complications of type 1 diabetes mellitus. Radiologists are integral members of the multidisciplinary transplantation team involved in these procedures, with multimodality imaging serving as the mainstay for early recognition and management of transplant related complications. This review highlights the transplantation procedures available for patients with type 1 Diabetes Mellitus with a focus on the imaging appearance of transplantation-related complications.

Ultrasound of pancreatic transplant complications: a primer for radiologists

Pancreatic transplantation is an established treatment for patients with type 1 diabetes patients and select type 2 diabetes patients, with excellent survival rates as graft health is evaluated through regular imaging and early detection of complications. Amongst the various imaging methods that may aid in diagnosis of pancreatic transplant complications, ultrasound is a widely available, quick, portable, and cost-effective technique, often used as the sole method to assess for pancreatic transplant complications. When assessing a patient with a pancreatic transplant, the radiologist should be methodical in assessing the vasculature, the pancreatic parenchyma, and the peripancreatic regions. Complications can be categorised based on time from transplant and type of complications, and include vascular, parenchymal, and enteric/anastomotic complications. Doppler has a major role in the diagnosis of vascular complications including arterial and venous thrombosis, arterial stenosis, pseudoaneurysms, and haematomas. Pancreatic complications include rejections and pancreatitis, and are often diagnosed through a combination of clinical, laboratory, and imaging findings, such as pancreatic heterogeneity or the presence of pancreatic pseudocysts. Enteric/anastomotic complications include leaks and bowel obstructions, and may require cross-sectional imaging in addition to ultrasound. This review covers the most common and high-impact vascular, parenchymal, and enteric/anastomotic complications that should be considered in every radiologist's search pattern when assessing a pancreatic graft, as well as their respective postoperative timeframes.

Pancreatic Transplantation: Surgical Anatomy and Complications

Pancreatic transplantation is a complex surgical procedure performed for patients with chronic severe diabetes, often performed in combination with renal transplantation. Vascular and exocrine drainage anatomy varies depending on the surgical technique. Radiology plays a critical role in the diagnosis of postoperative complications, requiring an understanding of grayscale/Doppler ultrasound as well as computed tomography and MR imaging. In this review, we detail usual surgical methods and normal postoperative imaging appearances. We then review the most common complications following pancreatic transplants, emphasizing diagnostic features of vascular (arterial/venous), surgical, and diffuse parenchymal pathologic conditions on multiple imaging modalities.

Unlocking the post-transplant microenvironment for successful islet function and survival

Islet transplantation (IT) offers the potential to restore euglycemia for patients with type 1 diabetes mellitus (T1DM). Despite improvements in islet isolation techniques and immunosuppressive regimes, outcomes remain suboptimal with UK five-year graft survivals (5YGS) of 55% and most patients still requiring exogenous insulin after multiple islet infusions. Native islets have a significant non-endocrine component with dense extra-cellular matrix (ECM), important for islet development, cell survival and function. Collagenase isolation necessarily disrupts this complex islet microenvironment, leaving islets devoid of a supporting framework and increasing vulnerability of transplanted islets. Following portal venous transplantation, a liver injury response is potentially induced, which typically results in inflammation and ECM deposition from liver specific myofibroblasts. The impact of this response may have important impact on islet survival and function. A fibroblast response and ECM deposition at the kidney capsule and eye chamber alongside other implantation sites have been shown to be beneficial for survival and function. Investigating the implantation site microenvironment and the interactions of transplanted islets with ECM proteins may reveal therapeutic interventions to improve IT and stem-cell derived beta-cell therapy.

Endovascular management of giant common iliac artery pseudoaneurysm after complications in simultaneous pancreas-kidney transplant: a case report

Background

Pancreatic transplantation is a definitive treatment for selected patients with insulin-dependent diabetes. It is a technically challenging surgery, and vascular complications are the most common cause of pancreatic graft failure. Although rare, pancreas transplants present higher rates of pseudoaneurysms at the vascular anastomosis than other visceral transplants. We present a case of a simultaneous pancreas–kidney transplant complicated with graft failure and common iliac artery pseudoaneurysm that was successfully treated through endovascular techniques.

Case presentation

A 34-year-old White woman presented with abdominal pain and a history of type 1 diabetes mellitus, end-stage renal disease, and two previous pancreas transplantation failures. The first was a simultaneous pancreas–kidney transplantation performed 7 months prior that was complicated by pancreas graft thrombosis within 1 month and required graft resection. Five months later, she underwent a second pancreas transplantation with another pancreatic graft thrombosis requiring graft resection. Abdominal angiotomography revealed a pseudoaneurysm in the right common iliac artery at the point of the previous graft anastomosis. The patient was successfully treated endovascularly with a covered stent in the common iliac artery.

Conclusion

Stent graft implantation for the treatment of common iliac artery pseudoaneurysm as a complication of simultaneous pancreas–kidney transplantation is a safe and feasible procedure.

Pseudocyst of Pancreas Transplant Allograft: A Case Report

BACKGROUND

Pancreatic pseudocysts are rarely reported complications of pancreas transplant.

CASE

We present a case of a patient with simultaneous pancreas and kidney transplant with bladder exocrine drainage who developed reflux pancreatitis and symptomatic pancreatic pseudocyst as a result of neuropathic bladder, 15 years after the original transplant. He was initially managed with percutaneous aspiration and drainage along with Foley catheter placement to help with bladder emptying. But the pseudocyst recurred after drains and Foley were removed. Eventually, he underwent an enteric conversion of the pancreas allograft with resolution of his symptoms and the pseudocyst.

CONCLUSIONS

Enteric conversion should be considered in cases of bladder-drained pancreas transplants with recurrent reflux pancreatitis and/or pseudocyst formation.

Beware the band adhesion: an unexpected cause of double obstruction following intraperitoneal kidney transplantation

Small bowel obstruction (SBO) following intraperitoneal renal transplantation, either solitary or due to simultaneous pancreas-kidney transplantation, is a known complication. While SBO is most commonly due to adhesions, there have been documented cases of internal herniation following simultaneous pancreas-kidney transplantation with enteric drainage due to the formation of a mesenteric defect. We present a unique complication in which the transplant ureter has caused strangulation and necrosis of a length of small intestine. The transplant ureter was mistaken for a band adhesion and divided. Post-operative anuria signalled this difficult diagnosis. Subsequent re-look laparotomy and ureteric reimplantation with Boari flap were required. Therefore, it is important to consider the ureter as a cause of internal herniation in kidney transplant patients and recognize that a band adhesion within the pelvis may in fact be the transplant ureter, obstructing a loop of small intestine beneath its course.

Pancreatic transplantation with duodenoduodenostomy drainage: technique, normal radiological appearance and complications

Pancreas transplantation is considered the curative treatment for severe type 1 diabetes mellitus in selected cases. Since the first procedure in 1966, surgical techniques have been improved. The current trend among most medical centers, as well as at our Institution, is enteric drainage and systemic venous or portal anastomosis. The aim of this pictorial essay is to describe the main imaging features of pancreatic transplantation with duodenoduodenostomy drainage.

Pancreatic transplantation: Brief review of the current evidence

Kidney transplantation is the treatment of choice for management of end-stage renal disease. However, in diabetic patients, the underlying metabolic disturbance will persist and even may get worse after isolated kidney transplantation. Pancreatic transplantation in humans was first introduced in 1966. The initial outcome was disappointing. However, this was changed after the improvement of surgical techniques together with better patient selection and the availability of potent and better-tolerated immune-suppression like cyclosporine and induction antibodies. Combined kidney and pancreas transplantation will not only solve the problem of organ failure, but it will also stabilise or even reverse the metabolic complications of diabetes. Combined kidney and pancreas transplantation have the best long term outcome in diabetic cases with renal failure. Nevertheless, at the cost of an initial increase in morbidity and risk of mortality. Other transplantation options include pancreas after kidney transplantation and islet cell transplantation. We aim by this work to explore various options which can be offered to a diabetic patient with advanced chronic kidney disease. Our work will provide a simplified, yet up-to-date information regarding the different management options for those diabetic chronic kidney failure patients.

Imaging in pancreas transplantation complications: Temporal classification

Pancreatic transplantation is a therapeutic option for both poorly controlled cases of diabetes mellitus and patients with advanced diabetic nephropathy. It is important for radiologists to know the different surgical techniques as well as the typical radiological appearance after pancreatic transplantation, in order to accurately identify the complications. These complications can be classified according to the period of time after the transplantation in which they typically occur: immediate (first 24 hours), early (24-72 hours), intermediate (72 hours to weeks) and late (months). An accurate and early diagnosis of pancreas transplantation complications is essential to start the adequate treatment and increase the chances of graft survival.

Imaging of Pancreas Transplantation and Its Complications

Whole pancreas transplantation is an effective treatment for obtaining euglycemic status in patients with insulin-dependent diabetes mellitus, and is usually performed concurrent with renal transplantation in the affected patient. This article discusses complex surgical anatomical details of pancreas transplantation including surgical options for endocrine and exocrine drainage pathways. It then describes several possible complications related to surgical factors in the immediate post operative period followed by other complications related to systemic issues, vasculature, and the pancreatic parenchyma.