title: Diffusion-weighted imaging in characterization of cystic pancreatic lesions.
abstract: OBJECTIVE
  To evaluate whether apparent diffusion coefficient (ADC) measurements from diffusion-weighted imaging (DWI) can characterize or predict the malignant potential of cystic pancreatic lesions.
  
  
  METHODS
  Retrospective review of the magnetic resonance imaging (MRI) database over a 2-year period revealed 136 patients with cystic pancreatic lesions. Patients with DWI studies and histological confirmation of cystic mass were included. In patients with known pancreatitis, lesions with amylase content of >1000 IU/l that resolved on subsequent scans were included as pseudocysts. ADC of cystic lesions was measured by two independent reviewers. These values were then compared to categorize these lesions as benign or malignant using conventional MRI sequences.
  
  
  RESULTS
  Seventy lesions were analysed: adenocarcinoma (n=4), intraductal papillary mucinous neoplasm (IPMN; n=28), mucinous cystic neoplasm (MCN; n=9), serous cystadenoma (n=16), and pseudocysts (n=13). There was no difference between ADC values of malignant and non-malignant lesions (p=0.06), between mucinous and serous tumours (p=0.12), or between IPMN and MCN (p=0.42). ADC values for low-grade IPMN were significantly higher than those for high-grade or invasive IPMN (p=0.03).
  
  
  CONCLUSIONS
  ADC values may be helpful in deciding the malignant potential of IPMN. However, they are not useful in differentiating malignant from benign lesions or for characterizing cystic pancreatic lesions.
authors: Department of Radiology, Indiana University School of Medicine, Indianapolis, IN, USA. ksandras@iupui.edu
authors: K
authors: K
authors: Sandrasegaran
authors: F M
authors: FM
authors: Akisik
authors: A A
authors: AA
authors: Patel
authors: M
authors: M
authors: Rydberg
authors: H M
authors: HM
authors: Cramer
authors: N P
authors: NP
authors: Agaram
authors: C M
authors: CM
authors: Schmidt