title: Focal Liver Lesions Classification and Characterization: What Value Do DWI and ADC Have?
abstract: OBJECTIVE
  The aim of this work was to analyze the value of diffusion-weighted imaging (DWI) in the classification/characterization of focal liver lesions (FLLs).
  
  
  METHODS
  Retrospective study, approved by ethical board, of 100 proven FLLs (20 hemangiomas, 20 focal nodular hyperplasia, 20 dysplastic nodules, 20 hepatocellular carcinomas, and 20 metastases) was performed by 1.5-T MR. For each lesion, 2 readers, blinded of medical history, have evaluated 6 sets of images: set A (T1/T2-weighted images), set B (set A + DWI), set C (set B + apparent diffusion coefficient [ADC] map), set D (set A + dynamic and hepatobiliary phases), set E (set D + DWI), set F (set E + ADC map).
  
  
  RESULTS
  In unenhanced images, the evaluation of the ADC improves the accuracy in classification/characterization (+9%/14%, respectively), whereas in enhanced images the accuracy was increased by DWI (+7%/12%, respectively) and ADC (+13%/19%, respectively). Diffusion-weighted imaging does not improve classification/characterization of hemangiomas, may be useful in focal nodular hyperplasia/dysplastic nodules vs metastases/hepatocellular carcinoma differentiation, and increases the classification/characterization of metastases in both unenhanced and enhanced images.
  
  
  CONCLUSIONS
  Diffusion-weighted imaging may improve classification/characterization of FLLs at unenhanced/enhanced examinations.
authors.affiliation: From the Department of Experimental and Clinical Biomedical Sciences, Radiodiagnostic Unit No 2, University of Florence, Azienda Ospedaliero-Universitaria Careggi, Florence, Italy.
authors.forename: Linda
authors.initials: L
authors.lastname: Calistri
authors.forename: Alessandro
authors.initials: A
authors.lastname: Castellani
authors.forename: Benedetta
authors.initials: B
authors.lastname: Matteuzzi
authors.forename: Elisa
authors.initials: E
authors.lastname: Mazzoni
authors.forename: Silvia
authors.initials: S
authors.lastname: Pradella
authors.forename: Stefano
authors.initials: S
authors.lastname: Colagrande
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000465:Algorithms; D038524:Diffusion Magnetic Resonance Imaging / Q000379:methods*; D005260:Female; D006801:Humans; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D008113:Liver Neoplasms / Q000145:classification / Q000175:diagnosis / Q000000981:diagnostic imaging* / Q000473:pathology*; D008297:Male; D008875:Middle Aged; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D055815:Young Adult