title: Volumetric segmentation of ADC maps and utility of standard deviation as measure of tumor heterogeneity in soft tissue tumors.
abstract: OBJECTIVE
  Determine interobserver concordance of semiautomated three-dimensional volumetric and two-dimensional manual measurements of apparent diffusion coefficient (ADC) values in soft tissue masses (STMs) and explore standard deviation (SD) as a measure of tumor ADC heterogeneity.
  
  
  RESULTS
  Concordance correlation coefficients for mean ADC increased with more extensive sampling. Agreement on the SD of tumor ADC values was better for large regions of interest and multislice methods. Correlation between mean and SD ADC was low, suggesting that these parameters are relatively independent.
  
  
  CONCLUSIONS
  Mean ADC of STMs can be determined by volumetric quantification with high interobserver agreement. STM heterogeneity merits further investigation as a potential imaging biomarker that complements other functional magnetic resonance imaging parameters.
authors.affiliation: Department of Radiology and Imaging Sciences, Emory University Hospital, Atlanta, GA. Electronic address: AdamSinger82@gmail.com.
authors.forename: Adam D
authors.initials: AD
authors.lastname: Singer
authors.affiliation: Department of Radiology, University of Miami, Miami, FL.
authors.forename: Pradip M
authors.initials: PM
authors.lastname: Pattany
authors.affiliation: Department of Radiology, Johns Hopkins University, Baltimore, MD.
authors.forename: Laura M
authors.initials: LM
authors.lastname: Fayad
authors.affiliation: Department of Radiology, University of Wisconsin, Madison, WI.
authors.forename: Jonathan
authors.initials: J
authors.lastname: Tresley
authors.affiliation: Department of Radiology, University of Miami, Miami, FL.
authors.forename: Ty K
authors.initials: TK
authors.lastname: Subhawong
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D038524:Diffusion Magnetic Resonance Imaging / Q000379:methods*; D005240:Feasibility Studies; D005260:Female; D006801:Humans; D021621:Imaging, Three-Dimensional / Q000379:methods*; D008297:Male; D008875:Middle Aged; D015588:Observer Variation; D012189:Retrospective Studies; D012509:Sarcoma / Q000000981:diagnostic imaging*; D012983:Soft Tissue Neoplasms / Q000000981:diagnostic imaging*; D055815:Young Adult
keywords: ADC; DWI; Quantification; Sarcoma; Volumetric