title: DW-MRI of liver lesions: can a single ADC-value represent the entire lesion?
abstract: OBJECTIVE
  To evaluate whether focal liver lesions (FLLs) exhibit a homogeneous appearance on apparent diffusion coefficient (ADC) maps and whether there is inter-section variation in the calculated ADC values of FLLs (inter-section range).
  
  
  METHODS
  Eighty-eight patients with 128 FLLs (70 benign, 58 malignant) who underwent abdominal magnetic resonance imaging (MRI) including diffusion-weighted (DW)-MRI were included. Two observers evaluated variation of signal intensity of each FLL within each ADC map image (intra-section) and among different ADC map images through the lesion (inter-section). ADC values of each FLL and neighbouring liver parenchyma were measured on all sections. The inter-section range of FLLs was compared with the neighbouring liver parenchyma.
  
  
  RESULTS
  Intra-section inhomogeneity was noted in 39.8% (97/244 sections) and 38.9% (95/244) of benign lesions, and 61% (114/187 sections) and 61.5% (115/187) of malignant lesions, by observer 1 and observer 2, respectively. Inter-section inhomogeneity was noted in 25.7% (18/70) and 27.1% (19/70) of benign lesions, and 51.7% (30/58) and 50% (29/58) of malignant lesions, by observer 1 and observer 2, respectively. The inter-section range for both benign (0.28 × 10(-3) mm(2)/s) and malignant (0.25 × 10(-3) mm(2)/s) FLLs were significantly greater than that of liver parenchyma surrounding benign (0.16 × 10(-3) mm(2)/s, p < 0.001) and malignant (0.14 × 10(-3) mm(2)/s, p = 0.01) FLLs.
  
  
  CONCLUSIONS
  Due to intra-/inter-section variations in ADC values of benign and malignant FLLs, a single ADC value may not reliably represent the entire lesion.
authors.affiliation: Department of Radiology, The University of Chicago, Chicago, IL, USA; Ludwig-Maximilians-University Hospital Munich, Institute for Clinical Radiology, Munich, Germany. Electronic address: christine.schmid-tannwald@med.uni-muenchen.de.
authors.forename: C
authors.initials: C
authors.lastname: Schmid-Tannwald
authors.affiliation: Department of Radiology, The University of Chicago, Chicago, IL, USA.
authors.forename: F
authors.initials: F
authors.lastname: Dahi
authors.affiliation: Department of Radiology, The University of Chicago, Chicago, IL, USA.
authors.forename: Y
authors.initials: Y
authors.lastname: Jiang
authors.affiliation: Department of Radiology, The University of Chicago, Chicago, IL, USA; Philips Healthcare, MR Clinical Science, Cleveland, OH, USA.
authors.forename: M K
authors.initials: MK
authors.lastname: Ivancevic
authors.affiliation: Ludwig-Maximilians-University Hospital Munich, Institute for Clinical Radiology, Munich, Germany.
authors.forename: C
authors.initials: C
authors.lastname: Rist
authors.affiliation: Department of Radiology, The University of Chicago, Chicago, IL, USA.
authors.forename: I
authors.initials: I
authors.lastname: Sethi
authors.affiliation: Department of Radiology, The University of Chicago, Chicago, IL, USA.
authors.forename: J
authors.initials: J
authors.lastname: Oommen
authors.affiliation: Department of Radiology, The University of Chicago, Chicago, IL, USA.
authors.forename: A
authors.initials: A
authors.lastname: Oto
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D003937:Diagnosis, Differential; D038524:Diffusion Magnetic Resonance Imaging / Q000379:methods; D005260:Female; D006801:Humans; D007089:Image Enhancement; D007091:Image Processing, Computer-Assisted; D008099:Liver / Q000473:pathology*; D008113:Liver Neoplasms / Q000473:pathology*; D008297:Male; D008875:Middle Aged; D015588:Observer Variation; D012372:ROC Curve; D015203:Reproducibility of Results; D012189:Retrospective Studies