Changes in classification schemes for acute pancreatitis

Atlanta Classification – 1992	Revised Atlanta Classification – 2011
Interstitial pancreatitis	Interstitial edematous pancreatitis (IEP)
Pancreatic necrosis	Necrotizing pancreatitis Pancreatic necrosis with peripancreatic necrosis Pancreatic necrosis alone Peripancreatic necrosis alone
<4 weeks after onset of pancreatitis	<4 weeks after onset of pancreatitis
Acute fluid collection	Acute fluid collection (AFC) Acute necrotic collection (ANC) Pancreatic necrosis with peripancreatic necrosis Pancreatic necrosis alone Peripancreatic necrosis alone
>4 weeks after onset of pancreatitis	>4 weeks after onset of pancreatitis
Pancreatic pseudocyst	Pancreatic pseudocyst
Pancreatic abscess	Walled-off necrosis (WON) Pancreatic necrosis with peripancreatic necrosis Pancreatic necrosis alone Peripancreatic necrosis alone