Revised Atlanta Classification for Acute Pancreatitis: A Pictorial Essay

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Use of the revised Atlanta classification in imaging of acute pancreatitis is discussed, with emphasis on distinguishing between various pancreatitis-associated collections such that the new lexicon can be implemented immediately by the radiologist, thereby facilitating accurate communication with referring providers.

The 2012 revised Atlanta classification is an update of the original 1992 Atlanta classification, a standardized clinical and radiologic nomenclature for acute pancreatitis and associated complications based on research advances made over the past 2 decades. Acute pancreatitis is now divided into two distinct subtypes, necrotizing pancreatitis and interstitial edematous pancreatitis (IEP), based on the presence or absence of necrosis, respectively. The revised classification system also updates confusing and sometimes inaccurate terminology that was previously used to describe pancreatic and peripancreatic collections. As such, use of the terms acute pseudocyst and pancreatic abscess is now discouraged. Instead, four distinct collection subtypes are identified on the basis of the presence of pancreatic necrosis and time elapsed since the onset of pancreatitis. Acute peripancreatic fluid collections (APFCs) and pseudocysts occur in IEP and contain fluid only. Acute necrotic collections (ANCs) and walled-off necrosis (WON) occur only in patients with necrotizing pancreatitis and contain variable amounts of fluid and necrotic debris. APFCs and ANCs occur within 4 weeks of disease onset. After this time, APFCs or ANCs may either resolve or persist, developing a mature wall to become a pseudocyst or a WON, respectively. Any collection subtype may become infected and manifest as internal gas, though this occurs most commonly in necrotic collections. In this review, the authors present a practical image-rich guide to the revised Atlanta classification system, with the goal of fostering implementation of the revised system into radiology practice, thereby facilitating accurate communication among clinicians and reinforcing the radiologist’s role as a key member of a multidisciplinary team in treating patients with acute pancreatitis.

©RSNA, 2016

An earlier incorrect version of this article appeared online. This article was corrected on March 28, 2019.


  • 1. Bradley EL 3rd. A clinically based classification system for acute pancreatitis: summary of the International Symposium on Acute Pancreatitis, Atlanta, Ga, September 11–13, 1992. Arch Surg 1993;128(5):586–590. Crossref, MedlineGoogle Scholar
  • 2. Banks PA, Bollen TL, Dervenis C, et al. Classification of acute pancreatitis 2012: revision of the Atlanta classification and definitions by international consensus. Gut 2013;62(1):102–111. Crossref, MedlineGoogle Scholar
  • 3. The Pancreas Club, Inc. Revision of the Atlanta classification of acute pancreatitis. Available at: Published April 9, 2008. Accessed March 28, 2015. Google Scholar
  • 4. Thoeni RF. The revised Atlanta classification of acute pancreatitis: its importance for the radiologist and its effect on treatment. Radiology 2012;262(3):751–764. LinkGoogle Scholar
  • 5. Bollen TL. Imaging of acute pancreatitis: update of the revised Atlanta classification. Radiol Clin North Am 2012;50(3):429–445. Crossref, MedlineGoogle Scholar
  • 6. Sheu Y, Furlan A, Almusa O, Papachristou G, Bae KT. The revised Atlanta classification for acute pancreatitis: a CT imaging guide for radiologists. Emerg Radiol 2012;19(3):237–243. Crossref, MedlineGoogle Scholar
  • 7. Bollen TL, Besselink MG, van Santvoort HC, Gooszen HG, van Leeuwen MS. Toward an update of the Atlanta classification on acute pancreatitis: review of new and abandoned terms. Pancreas 2007;35(2):107–113. Crossref, MedlineGoogle Scholar
  • 8. Dunnick NR, Langlotz CP. The radiology report of the future: a summary of the 2007 Intersociety Conference. J Am Coll Radiol 2008;5(5):626–629. Crossref, MedlineGoogle Scholar
  • 9. Ellenbogen PH. BI-RADS: revised and replicated. J Am Coll Radiol 2014;11(1):2. Crossref, MedlineGoogle Scholar
  • 10. Yadav D, Lowenfels AB. The epidemiology of pancreatitis and pancreatic cancer. Gastroenterology 2013;144(6):1252–1261. Crossref, MedlineGoogle Scholar
  • 11. Petrov MS, Windsor JA. Classification of the severity of acute pancreatitis: how many categories make sense? Am J Gastroenterol 2010;105(1):74–76. Crossref, MedlineGoogle Scholar
  • 12. Baker ME, Nelson RC, Rosen MP, et al. ACR Appropriateness Criteria acute pancreatitis. Ultrasound Q 2014;30(4):267–273. Crossref, MedlineGoogle Scholar
  • 13. Singh VK, Bollen TL, Wu BU, et al. An assessment of the severity of interstitial pancreatitis. Clin Gastroenterol Hepatol 2011;9(12):1098–1103. Crossref, MedlineGoogle Scholar
  • 14. Marshall JC, Cook DJ, Christou NV, Bernard GR, Sprung CL, Sibbald WJ. Multiple organ dysfunction score: a reliable descriptor of a complex clinical outcome. Crit Care Med 1995;23(10):1638–1652. Crossref, MedlineGoogle Scholar
  • 15. Spanier BW, Nio Y, van der Hulst RW, Tuynman HA, Dijkgraaf MG, Bruno MJ. Practice and yield of early CT scan in acute pancreatitis: a Dutch observational multicenter study. Pancreatology 2010;10(2-3):222–228. Crossref, MedlineGoogle Scholar
  • 16. Lenhart DK, Balthazar EJ. MDCT of acute mild (nonnecrotizing) pancreatitis: abdominal complications and fate of fluid collections. AJR Am J Roentgenol 2008;190(3):643–649. Crossref, MedlineGoogle Scholar
  • 17. Sandrasegaran K, Tann M, Jennings SG, et al. Disconnection of the pancreatic duct: an important but overlooked complication of severe acute pancreatitis. RadioGraphics 2007;27(5):1389–1400. LinkGoogle Scholar
  • 18. Kamal A, Singh VK, Akshintala VS, et al. CT and MRI assessment of symptomatic organized pancreatic fluid collections and pancreatic duct disruption: an interreader variability study using the revised Atlanta classification 2012. Abdom Imaging 2015;40(6):1608–1616. Crossref, MedlineGoogle Scholar
  • 19. Freeman ML, Werner J, van Santvoort HC, et al. Interventions for necrotizing pancreatitis: summary of a multidisciplinary consensus conference. Pancreas 2012;41(8):1176–1194. Crossref, MedlineGoogle Scholar
  • 20. Tüney D, Altun E, Barlas A, Yegen C. Pancreatico-colonic fistula after acute necrotizing pancreatitis: diagnosis with spiral CT using rectal water soluble contrast media. JOP 2008;9(1):26–29. MedlineGoogle Scholar
  • 21. Kochhar R, Jain K, Gupta V, et al. Fistulization in the GI tract in acute pancreatitis. Gastrointest Endosc 2012;75(2):436–440. Crossref, MedlineGoogle Scholar
  • 22. van Baal MC, Bollen TL, Bakker OJ, et al. The role of routine fine-needle aspiration in the diagnosis of infected necrotizing pancreatitis. Surgery 2014;155(3):442–448. Crossref, MedlineGoogle Scholar
  • 23. Türkvatan A, Erden A, Türkoğlu MA, Seçil M, Yüce G. Imaging of acute pancreatitis and its complications. II. Complications of acute pancreatitis. Diagn Interv Imaging 2015;96(2):161–169. Crossref, MedlineGoogle Scholar
  • 24. Memiş A, Parildar M. Interventional radiological treatment in complications of pancreatitis. Eur J Radiol 2002;43(3):219–228. Crossref, MedlineGoogle Scholar
  • 25. Shyu JY, Sainani NI, Sahni VA, et al. Necrotizing pancreatitis: diagnosis, imaging, and intervention. RadioGraphics 2014;34(5):1218–1239. LinkGoogle Scholar
  • 26. van Santvoort HC, Besselink MG, Bakker OJ, et al. A step-up approach or open necrosectomy for necrotizing pancreatitis. N Engl J Med 2010;362(16):1491–1502. Crossref, MedlineGoogle Scholar
  • 27. Madenci AL, Michailidou M, Chiou G, Thabet A, Fernández-del Castillo C, Fagenholz PJ. A contemporary series of patients undergoing open debridement for necrotizing pancreatitis. Am J Surg 2014;208(3):324–331. Crossref, MedlineGoogle Scholar
  • 28. Wu BU, Banks PA. Clinical management of patients with acute pancreatitis. Gastroenterology 2013;144(6):1272–1281. Crossref, MedlineGoogle Scholar
  • 29. Varadarajulu S, Christein JD, Tamhane A, Drelichman ER, Wilcox CM. Prospective randomized trial comparing EUS and EGD for transmural drainage of pancreatic pseudocysts (with videos). Gastrointest Endosc 2008;68(6):1102–1111. Crossref, MedlineGoogle Scholar

Article History

Received: Apr 6 2015
Revision requested: June 30 2015
Revision received: Aug 10 2015
Accepted: Aug 31 2015
Published online: May 10 2016
Published in print: May 2016