title: Morphological features of fluid collections on endoscopic ultrasound in acute necrotizing pancreatitis: do they change over time?
abstract: BACKGROUND
  There have been attempts to develop universally applicable nomenclature for pancreatic fluid collections (PFCs) in acute pancreatitis. But PFCs following acute necrotizing pancreatitis (ANP) has not been studied by sensitive imaging techniques like endoscopic ultrasound (EUS). The aim of the study was to prospectively study morphological structure of pancreatic fluid collections occurring after ANP by serial EUS.
  
  
  METHODS
  Patients with ANP having PFC at ≥4 weeks of onset of symptoms seen at our center from October 2011 to November 2012 were prospectively followed up with EUS at 6 weeks, 3 months and 6 months respectively and the amount of solid content in the collection was quantified as percentage amount of echogenic material. The symptomatic patients undergoing EUS/percutaneous drainage also underwent EUS prior to drainage for assessment of solid content.
  
  
  RESULTS
  Of the 54 patients enrolled, 7 patients were lost to follow up or refused EUS. Forty seven patients (34 males; mean age 36.7±11.6 years) were studied. Etiology of acute pancreatitis was alcohol (n=22), gallstones (n=10), idiopathic (10), gallstones+alcohol (n=3) and drug induced (n=2). Contrast enhanced computed tomography done after 3 days of onset of ANP had shown less than 30%, 30-50% and more than 50% necrosis in 6 (13%), 14 (30%) and 27 (57%) patients respectively. On EUS at 6 weeks, 41/47 (87%) patients had fluid collection with solid debris. Follow up EUS at 3 and 6 months revealed progressively decreasing solid content in PFCs.
  
  
  CONCLUSIONS
  All PFCs following ANP may not have solid necrotic content and over a period of time necrotic content tends to liquefy. This may have therapeutic implications.
authors: Department of Gastroenterology (Surinder S. Rana, Deepak K. Bhasin, Yalaka Rami Reddy, Vishal Sharma, Chalapathi Rao, Ravi K. Sharma), Post Graduate Institute of Medical Education and Research (PGIMER), Chandigarh, India.
authors: Surinder S
authors: SS
authors: Rana
authors: Department of Gastroenterology (Surinder S. Rana, Deepak K. Bhasin, Yalaka Rami Reddy, Vishal Sharma, Chalapathi Rao, Ravi K. Sharma), Post Graduate Institute of Medical Education and Research (PGIMER), Chandigarh, India.
authors: Deepak K
authors: DK
authors: Bhasin
authors: Department of Gastroenterology (Surinder S. Rana, Deepak K. Bhasin, Yalaka Rami Reddy, Vishal Sharma, Chalapathi Rao, Ravi K. Sharma), Post Graduate Institute of Medical Education and Research (PGIMER), Chandigarh, India.
authors: Yalaka Rami
authors: YR
authors: Reddy
authors: Department of Gastroenterology (Surinder S. Rana, Deepak K. Bhasin, Yalaka Rami Reddy, Vishal Sharma, Chalapathi Rao, Ravi K. Sharma), Post Graduate Institute of Medical Education and Research (PGIMER), Chandigarh, India.
authors: Vishal
authors: V
authors: Sharma
authors: Department of Gastroenterology (Surinder S. Rana, Deepak K. Bhasin, Yalaka Rami Reddy, Vishal Sharma, Chalapathi Rao, Ravi K. Sharma), Post Graduate Institute of Medical Education and Research (PGIMER), Chandigarh, India.
authors: Chalapathi
authors: C
authors: Rao
authors: Department of Gastroenterology (Surinder S. Rana, Deepak K. Bhasin, Yalaka Rami Reddy, Vishal Sharma, Chalapathi Rao, Ravi K. Sharma), Post Graduate Institute of Medical Education and Research (PGIMER), Chandigarh, India.
authors: Ravi K
authors: RK
authors: Sharma
authors: Department of Surgery (Rajesh Gupta), Post Graduate Institute of Medical Education and Research (PGIMER), Chandigarh, India.
authors: Rajesh
authors: R
authors: Gupta
keywords: Endoscopic ultrasound; acute pancreatitis; computed tomography; walled off pancreatic necrosis