More than half of acute peripancreatic fluid collections resolve without intervention in the first several weeks, and intervention is rarely pursued to avoid potentially infecting a typically sterile collection. The remaining acute peripancreatic fluid collections that do not resolve become pseudocysts after 4 weeks and are characterized by a fibrous capsule. CT is the most common modality for identifying pseudocysts and their relationship to surrounding structures prior to intervention. Acute necrotic collections are associated with pancreatic or peripancreatic necrosis and contain varying amounts of fluid and necrotic material and are of varying sizes and shapes [3]. On CT, these collections have heterogeneous, varied densities (fluid, fat, and solid material) with no or an incompletely defined wall. It can be challenging to distinguish collections that contain varying amounts of fluid and necrotic debris from pure fluid containing acute peripancreatic fluid collections on CT abdomen and pelvis with IV contrast and necrotic material within collections is often overlooked. The presence of fat globules on CT is usually associated with the presence of large amounts of debris within a collection [26]. MRI and possibly US are better at demonstrating debris and necrotic material within these collections [21,26,27]. Accurate identification of necrotic debris is important for characterization; however, it is particularly important if drainage is considered, as residual, unrecognized debris after standard drainage increases the risk of infection. Acute necrotic collections may also be associated with disruption of the main pancreatic duct within the parenchymal necrosis, and CT has reduced sensitivity for identifying ductal abnormalities. CT abdomen and pelvis without IV contrast can help in the detection of fluid collections that may or may not be infected.
Acute Pancreatitis. More than half of acute peripancreatic fluid collections resolve without intervention in the first several weeks, and intervention is rarely pursued to avoid potentially infecting a typically sterile collection. The remaining acute peripancreatic fluid collections that do not resolve become pseudocysts after 4 weeks and are characterized by a fibrous capsule. CT is the most common modality for identifying pseudocysts and their relationship to surrounding structures prior to intervention. Acute necrotic collections are associated with pancreatic or peripancreatic necrosis and contain varying amounts of fluid and necrotic material and are of varying sizes and shapes [3]. On CT, these collections have heterogeneous, varied densities (fluid, fat, and solid material) with no or an incompletely defined wall. It can be challenging to distinguish collections that contain varying amounts of fluid and necrotic debris from pure fluid containing acute peripancreatic fluid collections on CT abdomen and pelvis with IV contrast and necrotic material within collections is often overlooked. The presence of fat globules on CT is usually associated with the presence of large amounts of debris within a collection [26]. MRI and possibly US are better at demonstrating debris and necrotic material within these collections [21,26,27]. Accurate identification of necrotic debris is important for characterization; however, it is particularly important if drainage is considered, as residual, unrecognized debris after standard drainage increases the risk of infection. Acute necrotic collections may also be associated with disruption of the main pancreatic duct within the parenchymal necrosis, and CT has reduced sensitivity for identifying ductal abnormalities. CT abdomen and pelvis without IV contrast can help in the detection of fluid collections that may or may not be infected.