title: Impact of ROI Positioning and Lesion Morphology on Apparent Diffusion Coefficient Analysis for the Differentiation Between Benign and Malignant Nonfatty Soft-Tissue Lesions.
abstract: OBJECTIVE
  The objective of our study was to assess the impact of two methods of apparent diffusion coefficient (ADC) selection on the diagnostic performance of DWI in the characterization of nonfatty soft-tissue masses.
  
  
  METHODS
  Sixty-five histologically confirmed soft-tissue tumors imaged from November 2009 through October 2012 were evaluated. The minimal ADC (ADCmin) and average ADC (ADCavg) values for each tumor were obtained using two ROI-positioning methods: manual and semiautomatic. Two readers correlated the findings to lesion histology and morphology on conventional MRI sequences.
  
  
  RESULTS
  The ADCmin values obtained using the manual method presented a better sensitivity with a similar specificity when compared with the ADCmin values obtained using the semiautomatic method (manual vs semiautomatic: 75-83% and 59-63% vs 58-67% and 63% and 63%, respectively). The interobserver agreement for the ADCmin values was similar between the ADC selection methods (intraclass correlation coefficient = 0.81 and 0.87 for manual and semiautomatic methods, respectively). In the subgroup of solid lesions, the ADCavg values obtained using the manual method offered a better sensitivity for benign-malignant differentiation (60-81% vs 60% and 60% for ADCavg and ADCmin, respectively).
  
  
  CONCLUSIONS
  The ADCmin values obtained with manual ROI positioning offered the best diagnostic performance for tumor characterization. The semiautomatic method yielded similar specificity values. For solid masses, the ADCavg values were better correlated with tumor histology than the ADCmin values.
authors.affiliation: 1 Service de Radiologie Guilloz, CHU Nancy, Rue du Maréchal de Lattre de Tassigny, 54000 Nancy, France.
authors.forename: Chloé
authors.initials: C
authors.lastname: Bonarelli
authors.affiliation: 1 Service de Radiologie Guilloz, CHU Nancy, Rue du Maréchal de Lattre de Tassigny, 54000 Nancy, France.|2 CICIT, Vandoeuvre-lès-Nancy, France.
authors.forename: Pedro Augusto Gondim
authors.initials: PA
authors.lastname: Teixeira
authors.affiliation: 1 Service de Radiologie Guilloz, CHU Nancy, Rue du Maréchal de Lattre de Tassigny, 54000 Nancy, France.|2 CICIT, Vandoeuvre-lès-Nancy, France.|3 INSERM, Nancy, France.
authors.forename: Gabriela
authors.initials: G
authors.lastname: Hossu
authors.affiliation: 1 Service de Radiologie Guilloz, CHU Nancy, Rue du Maréchal de Lattre de Tassigny, 54000 Nancy, France.
authors.forename: Jean-Baptiste
authors.initials: JB
authors.lastname: Meyer
authors.affiliation: 2 CICIT, Vandoeuvre-lès-Nancy, France.|3 INSERM, Nancy, France.
authors.forename: Bailiang
authors.initials: B
authors.lastname: Chen
authors.affiliation: 4 CHUV Lausanne, Lausanne, Switzerland.
authors.forename: Frédérique
authors.initials: F
authors.lastname: Gay
authors.affiliation: 1 Service de Radiologie Guilloz, CHU Nancy, Rue du Maréchal de Lattre de Tassigny, 54000 Nancy, France.
authors.forename: Alain
authors.initials: A
authors.lastname: Blum
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D003287:Contrast Media; D003937:Diagnosis, Differential; D038524:Diffusion Magnetic Resonance Imaging / Q000379:methods*; D005260:Female; D006801:Humans; D007090:Image Interpretation, Computer-Assisted; D008297:Male; D008875:Middle Aged; D056888:Patient Positioning; D011446:Prospective Studies; D012680:Sensitivity and Specificity; D012983:Soft Tissue Neoplasms / Q000473:pathology*
chemical_list: D003287:Contrast Media
keywords: apparent diffusion coefficient (ADC) calculation; diffusion-weighted MRI; postprocessing method; soft tissues; tumoral characterization