Evaluation of vascular complications of pancreas transplantation with high-spatial-resolution contrast-enhanced MR angiography

Purpose: To retrospectively evaluate high-spatial-resolution contrast material-enhanced three-dimensional (3D) magnetic resonance (MR) angiography for assessment of vascular complications of pancreas allografts. Materials and Methods: The institutional review board approved the study and waived the requirement for informed patient consent owing to the retrospective nature of the study with use of an anonymous-subject database. The study was HIPAA compliant. The clinical and MR angiography findings in 11 patients (eight men, three women; mean age, 43 years; age range, 30-54 years) who had a history of pancreatic transplant dysfunction and underwent a total of 13 contrast-enhanced 3D MR angiography examinations were retrospectively reviewed. Comparison with conventional angiography findings was possible for four MR angiography examinations, comparison with surgical findings was possible for two examinations, and clinical follow-up was possible for all examinations. Two observers in consensus and blinded to the clinical results performed image analysis of the arterial and venous segments. Classification agreement was assessed with quadratic weighted kappa statistics. Results: Ten MR angiography examinations revealed vascular complications or signs suggestive of rejection. Only three examinations were considered to have completely normal results. All major complications were detected and included complete or partial arterial graft occlusion, stenosis of the arterial Y-graft caused by a kink, complete venous thrombosis, and arteriovenous fistula with pseudoaneurysm formation. For 46 arterial segments and 15 venous segments with angiographic and/or surgical comparison, overall agreement with MR angiography findings was nearly perfect (mean kappa, 0.983; standard error of the mean, 0.128). Conclusion: High-spatial-resolution MR angiography of pancreas allografts enables assessment of the arterial and venous vascular anatomy and can be used to reliably identify clinically relevant vascular complications.