Role of CT in Pancreatitis-AJR Review

In a structured review published in AJR by Murphy et al, authors have compiled updated imaging nomenclature for pancreatitis.  These points include when to call pseudocyt or when to call walled of necrosis on CT. Very useful for all residents. 

Key points from the review include

• CT is used to confirm the diagnosis of acute pancreatitis when the diagnosis is in doubt and to differentiate acute interstitial pancreatitis from necrotizing pancreatitis, which is a key element of the updated Atlanta nomenclature. 
• The acute interstitial variety accounts for 90–95% of cases, with acute necrotizing pancreatitis accounting for the remaining cases.
• Necrosis due to acute pancreatitis is best assessed on IV contrast-enhanced CT performed 40 seconds after injection.
• Simple fluid collections associated with acute interstitial pancreatitis are subdivided chronologically. A collection observed within approximately 4 weeks of acute pancreatitis onset is termed an “acute peripancreatic fluid collection (APFC).” A collection older than 4 weeks should have a thin wall and is termed a “pseudocyst.” Both APFCs and pseudocysts can be infected or sterile.
• Fluid collections associated with necrotizing pancreatitis are labeled on the basis of age and the presence of a capsule. Within 4 weeks of acute pancreatitis onset, a fluid collection associated with necrotizing pancreatitis is termed an “acute necrotic collection (ANC)” whereas an older collection is termed an area of “walled-off necrosis (WON)” if it has a perceptible wall on CT. The term “pseudocyst” is not used in the setting of necrotizing pancreatitis collections. 

Reference and further reading: 

Updated Imaging Nomenclature for Acute Pancreatitis

Kevin P. Murphy, Owen J. O'Connor, and Michael M. Maher

Read More: http://www.ajronline.org/doi/abs/10.2214/AJR.13.12222