title: Role of diffusion-weighted magnetic resonance imaging in the differential diagnosis of focal hepatic lesions.
abstract: OBJECTIVE
  To evaluate the utility of diffusion-weighted imaging (DWI) in screening and differential diagnosis of benign and malignant focal hepatic lesions.
  
  
  METHODS
  Magnetic resonance imaging (MRI) examinations were performed using the Signa Excite Xl Twin Speed 1.5T system (GE Healthcare, Milwaukee, WI, USA). Seventy patients who had undergone MRI of the liver [29 hepatocellular carcinomas (HCC), four cholangiocarcinomas, 34 metastatic liver cancers, 10 hemangiomas, and eight cysts] between April 2004 and August 2008 were retrospectively evaluated. Visualization of lesions, relative contrast ratio (RCR), and apparent diffusion coefficient (ADC) were compared between benign and malignant lesions on DWI. Superparamagnetic iron oxide (SPIO) was administered to 59 patients, and RCR was compared pre- and post-administration.
  
  
  RESULTS
  DWI showed higher contrast between malignant lesions (especially in multiple small metastatic cancers) and surrounding liver parenchyma than did contrast-enhanced computed tomography. ADCs (mean +/- SD x 10(-3) mm(2)/s) were significantly lower (P < 0.05) in malignant lesions (HCC: 1.31 +/- 0.28 and liver metastasis: 1.11 +/- 0.22) and were significantly higher in benign lesions (hemangioma: 1.84 +/- 0.37 and cyst: 2.61 +/- 0.45) than in the surrounding hepatic tissues. RCR between malignant lesions and surrounding hepatic tissues significantly improved after SPIO administration, but RCRs in benign lesions were not improved.
  
  
  CONCLUSIONS
  DWI is a simple and sensitive method for screening focal hepatic lesions and is useful for differential diagnosis.
authors.affiliation: Department of Surgery, Seirei Sakura Citizen Hospital, 2-36-2 Ebaradai, Sakura, Chiba 285-8765, Japan. naotk@sis.seirei.or.jp
authors.forename: Naoto
authors.initials: N
authors.lastname: Koike
authors.forename: Akihiro
authors.initials: A
authors.lastname: Cho
authors.forename: Katsuhiro
authors.initials: K
authors.lastname: Nasu
authors.forename: Kazuhiko
authors.initials: K
authors.lastname: Seto
authors.forename: Shigeyuki
authors.initials: S
authors.lastname: Nagaya
authors.forename: Yuji
authors.initials: Y
authors.lastname: Ohshima
authors.forename: Nobuhiro
authors.initials: N
authors.lastname: Ohkohchi
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D006528:Carcinoma, Hepatocellular / Q000175:diagnosis / Q000473:pathology; D003937:Diagnosis, Differential; D038524:Diffusion Magnetic Resonance Imaging / Q000379:methods*; D005260:Female; D006801:Humans; D008113:Liver Neoplasms / Q000175:diagnosis / Q000473:pathology; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies