title: Focal liver lesion detection and characterization with diffusion-weighted MR imaging: comparison with standard breath-hold T2-weighted imaging.
abstract: OBJECTIVE
  To retrospectively compare diffusion-weighted (DW) magnetic resonance (MR) imaging with standard breath-hold T2-weighted MR imaging for focal liver lesion (FLL) detection and characterization, by using consensus evaluation and other findings as the reference standard.
  
  
  METHODS
  Approval for this retrospective HIPAA-compliant study was obtained from the institutional review board; informed consent was waived. Fifty-three consecutive patients (30 men, 23 women; mean age, 60.7 years) with at least one FLL of 1 cm or greater in diameter were evaluated. Two independent observers reviewed DW (b values of 0, 50, and 500 sec/mm(2)) and T2-weighted images for FLL detection and characterization. Reference standard for diagnosis was obtained from consensus review by the two observers of DW, T2-weighted, and dynamic contrast material-enhanced images, pathologic data, and follow-up imaging results. Apparent diffusion coefficient (ADC) was measured for FLLs identified at consensus review. DW and T2-weighted images were compared for FLL detection and characterization by using a binary logistic regression model. Receiver operating characteristic curve analyses were conducted to evaluate the utility of ADC for diagnosis of malignancy.
  
  
  RESULTS
  Two hundred eleven FLLs (136 malignant, 75 benign) were detected at consensus review. Overall detection rate (averaged for two observers) was significantly higher for DW (87.7%) versus T2-weighted (70.1%) imaging (P < .001). FLL characterization was not significantly different between DW (89.1%) and T2-weighted (86.8%) imaging (P = .51). ADCs of malignant FLLs were significantly lower than those of benign FLLs (P < .001). The area under the curve for diagnosis of malignancy was 0.839, with sensitivity of 74.2%, specificity of 77.3%, positive predictive value of 85.5%, negative predictive value of 62.3%, and accuracy of 75.3%, by using a threshold ADC of less than 1.60 x 10(-3) mm(2)/sec.
  
  
  CONCLUSIONS
  DW MR imaging was better than standard breath-hold T2-weighted imaging for FLL detection and was equal to breath-hold T2-weighted imaging for FLL characterization.
authors.affiliation: Department of Radiology, New York University Medical Center, 530 First Ave, MRI, New York, NY 10016, USA.
authors.forename: Tejas
authors.initials: T
authors.lastname: Parikh
authors.forename: Stephen J
authors.initials: SJ
authors.lastname: Drew
authors.forename: Vivian S
authors.initials: VS
authors.lastname: Lee
authors.forename: Samson
authors.initials: S
authors.lastname: Wong
authors.forename: Elizabeth M
authors.initials: EM
authors.lastname: Hecht
authors.forename: James S
authors.initials: JS
authors.lastname: Babb
authors.forename: Bachir
authors.initials: B
authors.lastname: Taouli
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D016009:Chi-Square Distribution; D003287:Contrast Media; D038524:Diffusion Magnetic Resonance Imaging; D005260:Female; D019786:Gadolinium DTPA; D006801:Humans; D008113:Liver Neoplasms / Q000175:diagnosis* / Q000556:secondary; D016015:Logistic Models; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D012372:ROC Curve; D012189:Retrospective Studies
chemical_list: D003287:Contrast Media; D019786:Gadolinium DTPA