title: Acute interstitial edematous pancreatitis: Findings on non-enhanced MR imaging.
abstract: OBJECTIVE
  To study the appearances of acute interstitial edematous pancreatitis (IEP) on non-enhanced MR imaging.
  
  
  METHODS
  A total of 53 patients with IEP diagnosed by clinical features and laboratory findings were underwent MR imaging. MR imaging sequences included fast spoiled gradient echo (FSPGR) fat saturation axial T1-weighted imaging, gradient echo T1-weighted (in phase), single shot fast spin echo (SSFSE) T2-weighted, respiratory triggered (R-T) T2-weighted with fat saturation, and MR cholangiopancreatography. Using the MR severity score index, pancreatitis was graded as mild (0-2 points), moderate (3-6 points) and severe (7-10 points).
  
  
  RESULTS
  Among the 53 patients, IEP was graded as mild in 37 patients and as moderate in 16 patients. Forty-seven of 53 (89%) patients had at least one abnormality on MR images. Pancreas was hypointense relative to liver on FSPGR T1-weighted images in 18.9% of patients, and hyperintense in 25% and 30% on SSFSE T2-weighted and R-T T2-weighted images, respectively. The prevalences of the findings of IEP on R-T T2-weighted images were, respectively, 85% for pancreatic fascial plane, 77% for left renal fascial plane, 55% for peripancreatic fat stranding, 42% for right renal fascial plane, 45% for perivascular fluid, 40% for thickened pancreatic lobular septum and 25% for peripancreatic fluid, which were markedly higher than those on in-phase or SSFSE T2-weighted images (P<0.001).
  
  
  CONCLUSIONS
  IEP primarily manifests on non-enhanced MR images as thickened pancreatic fascial plane, left renal fascial plane, peripancreatic fat stranding, and peripancreatic fluid. R-T T2-weighted imaging is more sensitive than in-phase and SSFSE T2-weighted imaging for depicting IEP.
authors.affiliation: Department of Radiology, Affiliated Hospital of North Sichuan Medical College, Wenhua Road 63, Nanchong 637000, Sichuan Province, China. zhangxm@nsmc.edu.cn
authors.forename: Xiao-Ming
authors.initials: XM
authors.lastname: Zhang
authors.forename: Zhi-Song
authors.initials: ZS
authors.lastname: Feng
authors.forename: Qiong-Hui
authors.initials: QH
authors.lastname: Zhao
authors.forename: Chun-Ming
authors.initials: CM
authors.lastname: Xiao
authors.forename: Donald-G
authors.initials: DG
authors.lastname: Mitchell
authors.forename: Jian
authors.initials: J
authors.lastname: Shu
authors.forename: Nan-Lin
authors.initials: NL
authors.lastname: Zeng
authors.forename: Xiao-Xue
authors.initials: XX
authors.lastname: Xu
authors.forename: Jun-Yang
authors.initials: JY
authors.lastname: Lei
authors.forename: Xiao-Bing
authors.initials: XB
authors.lastname: Tian
mesh_terms: D000208:Acute Disease; D000293:Adolescent; D000328:Adult; D000368:Aged; D002648:Child; D004487:Edema / Q000473:pathology*; D005260:Female; D006801:Humans; D007902:Length of Stay; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D010195:Pancreatitis / Q000473:pathology*; D012189:Retrospective Studies; D012720:Severity of Illness Index