title: Added value of diffusion-weighted imaging to MR cholangiopancreatography with unenhanced mr imaging for predicting malignancy or invasiveness of intraductal papillary mucinous neoplasm of the pancreas.
abstract: OBJECTIVE
  To investigate the added value of diffusion-weighted imaging (DWI) to magnetic resonance cholangiopancreatography (MRCP) with unenhanced MR imaging for predicting the malignancy or invasiveness of intraductal papillary mucinous neoplasms (IPMNs).
  
  
  METHODS
  Following Institutional Review Board (IRB) approval, this retrospective study included 52 patients with surgically resected IPMNs and who underwent MRCP, unenhanced MRI, and DWI. Three blinded radiologists evaluated the two image sets, ie, MRCP with unenhanced MR images vs. the combined set with MRCP, unenhanced MR images, and DWI, and scored their confidence for malignancy or for invasiveness of IPMNs. The mean apparent diffusion coefficient (ADC) values of benign IPMNs and of intraductal mucinous carcinomas (IPMCs) were compared. The diagnostic accuracy was calculated using receiver operating characteristic (ROC) curve analysis.
  
  
  RESULTS
  The mean ADC of malignant IPMNs (2.05 ± 0.66 × 10(-3) mm(2) /sec) was significantly lower than that of benign IPMNs (2.95 ± 0.32 × 10(-3) mm(2) /sec, P < 0.0001). Invasive IPMCs (1.51 ± 0.32 × 10(-3) mm(2) /sec) showed significantly lower ADC than that of noninvasive IPMCs (2.67 ± 0.23 × 10(-3) mm(2) /sec, P = 0.0003). The area of diffusion restriction was more frequently seen in malignant IPMNs than in benign IPMNs (P < 0.00001). The addition of DWI to MRCP with unenhanced MRI did not show a significant improvement for predicting malignant IPMN (P> 0.05), but resulted in a tendency to improve the diagnostic accuracy for the prediction of invasive IPMN in two observers (P = 0.072, P = 0.085).
  
  
  CONCLUSIONS
  The addition of DWI to MRCP with unenhanced MRI may improve the diagnosis of malignant IPMN and further increase the prediction of invasive IPMC.
authors: Department of Radiology and Institute of Radiation Medicine, Seoul National University Hospital, Seoul, Korea.
authors: Koung Mi
authors: KM
authors: Kang
authors: Jeong Min
authors: JM
authors: Lee
authors: Cheong-Il
authors: CI
authors: Shin
authors: Jee Hyun
authors: JH
authors: Baek
authors: Seung Ho
authors: SH
authors: Kim
authors: Jeong Hee
authors: JH
authors: Yoon
authors: Joon Koo
authors: JK
authors: Han
authors: Byung Ihn
authors: BI
authors: Choi
mesh_terms: D002288:Adenocarcinoma, Mucinous / Q000473:pathology*; D000328:Adult; D000368:Aged; D021441:Carcinoma, Pancreatic Ductal / Q000473:pathology*; D002291:Carcinoma, Papillary / Q000473:pathology*; D049448:Cholangiopancreatography, Magnetic Resonance / Q000379:methods*; D003287:Contrast Media; D038524:Diffusion Magnetic Resonance Imaging / Q000379:methods*; D005260:Female; D006801:Humans; D007089:Image Enhancement / Q000379:methods; D008297:Male; D008875:Middle Aged; D064847:Multimodal Imaging / Q000379:methods; D009361:Neoplasm Invasiveness; D010190:Pancreatic Neoplasms / Q000473:pathology*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity
chemical_list: D003287:Contrast Media
keywords: MR cholangiopancreatography; diffusion-weighted imaging; intraductal papillary mucinous neoplasm; pancreas