Cross-sectional imaging of common and unusual complications after endoscopic retrograde cholangiopancreatography

Endoscopic retrograde cholangiopancreatography (ERCP) is currently a primarily therapeutic procedure that is extensively employed to treat several biliopancreatic disorders. Although widely considered a safe procedure, ERCP is associated with a non-negligible morbidity and occasional mortality. Due to the number and complexity of operative ERCPs performed, radiologists are increasingly faced with urgent requests for investigation of suspected post-procedural complications, which often have similar clinical and laboratory manifestations. This pictorial essay reviews the usual post-procedural CT findings, the clinical features and imaging appearances of common and unusual post-ERCP occurrences including interstitial oedematous and necrotising acute pancreatitis, haemorrhages, retroperitoneal and intraperitoneal duodenal perforations, infections and stent-related complications. Emphasis is placed on the pivotal role of multidetector CT, which is warranted after complex or prolonged ERCP procedures as it represents the most effective modality to detect and grade ERCP-related complications and to monitor nonsurgically treated patients. Timely diagnosis and optimal management require a combination of clinical and laboratory data with imaging appearances; therefore, this article aims to provide an increased familiarity with interpretation of early post-ERCP studies, particularly to triage those occurrences that require interventional or surgical treatment. In selected patients MRI allows imaging pancreatitis and abnormal collections without the use of ionising radiation. Teaching Points • Endoscopic retrograde cholangiopancreatography (ERCP) allows treating many biliopancreatic disorders.• Due to the number and complexity of procedures, post-ERCP complications are increasingly encountered.• Main complications include acute pancreatitis, haemorrhages, duodenal perforation and infections.• Diagnosis and management of complications rely on combined clinical, laboratory and imaging data.• Multidetector CT is most effective to diagnose, categorise and monitor post-ERCP complications.