Known pancreatic or peripancreatic fluid collections with continued abdominal pain, early satiety, nausea, vomiting, or signs of infection. Greater than 4 weeks after symptom onset. Local complications in AP include pancreatic or peripancreatic fluid collections. The classification of these fluid collections depends on timing and the presence of necrosis. Acute peripancreatic fluid collections usually develop in the early phase of interstitial edematous pancreatitis and may turn into a pancreatic pseudocyst as a delayed (>4 weeks) complication. A pseudocyst has a well-defined wall and does not contain solid material. In necrotizing pancreatitis, a collection in the early phase is an acute necrotic collection and develops into walled-off necrosis, which is surrounded by a detectible capsule, after 4 weeks [3]. Differentiating walled-off necrosis from pseudocysts that do not contain debris has important implications for management, as residual necrotic debris after drainage may lead to secondary infection. Pseudocysts can be drained by simple percutaneous or endoscopic techniques, as they are composed almost exclusively of fluid. Conversely, walled-off necrosis requires surgical debridement, direct endoscopic necrosectomy, insertion of larger caliber metallic cystgastrostomy stents, or ongoing percutaneous irrigation and drainage of necrotic debris [30]. Although increased clinical severity, particularly persistent organ failure, may suggest that collections likely intervention planning/selection are best represent walled-off necrosis, definitive characterization and accomplished with imaging. CT Abdomen and Pelvis CT of the abdomen and pelvis with IV contrast is historically the most commonly obtained initial test to evaluate the presence of pancreatic or peripancreatic fluid collections. It is also often used to follow-up symptomatic collections and for intervention planning. However, CT is limited in the quantification of debris and differentiation of pseudocysts from walled-off necrosis.
Acute Pancreatitis. Known pancreatic or peripancreatic fluid collections with continued abdominal pain, early satiety, nausea, vomiting, or signs of infection. Greater than 4 weeks after symptom onset. Local complications in AP include pancreatic or peripancreatic fluid collections. The classification of these fluid collections depends on timing and the presence of necrosis. Acute peripancreatic fluid collections usually develop in the early phase of interstitial edematous pancreatitis and may turn into a pancreatic pseudocyst as a delayed (>4 weeks) complication. A pseudocyst has a well-defined wall and does not contain solid material. In necrotizing pancreatitis, a collection in the early phase is an acute necrotic collection and develops into walled-off necrosis, which is surrounded by a detectible capsule, after 4 weeks [3]. Differentiating walled-off necrosis from pseudocysts that do not contain debris has important implications for management, as residual necrotic debris after drainage may lead to secondary infection. Pseudocysts can be drained by simple percutaneous or endoscopic techniques, as they are composed almost exclusively of fluid. Conversely, walled-off necrosis requires surgical debridement, direct endoscopic necrosectomy, insertion of larger caliber metallic cystgastrostomy stents, or ongoing percutaneous irrigation and drainage of necrotic debris [30]. Although increased clinical severity, particularly persistent organ failure, may suggest that collections likely intervention planning/selection are best represent walled-off necrosis, definitive characterization and accomplished with imaging. CT Abdomen and Pelvis CT of the abdomen and pelvis with IV contrast is historically the most commonly obtained initial test to evaluate the presence of pancreatic or peripancreatic fluid collections. It is also often used to follow-up symptomatic collections and for intervention planning. However, CT is limited in the quantification of debris and differentiation of pseudocysts from walled-off necrosis.