title: Interobserver agreement of semi-automated and manual measurements of functional MRI metrics of treatment response in hepatocellular carcinoma.
abstract: OBJECTIVE
  To assess the interobserver agreement in 50 patients with hepatocellular carcinoma (HCC) before and 1 month after intra-arterial therapy (IAT) using two semi-automated methods and a manual approach for the following functional, volumetric and morphologic parameters: (1) apparent diffusion coefficient (ADC), (2) arterial phase enhancement (AE), (3) portal venous phase enhancement (VE), (4) tumor volume, and assessment according to (5) the Response Evaluation Criteria in Solid Tumors (RECIST), and (6) the European Association for the Study of the Liver (EASL).
  
  
  METHODS
  This HIPAA-compliant retrospective study had institutional review board approval. The requirement for patient informed consent was waived. Tumor ADC, AE, VE, volume, RECIST, and EASL in 50 index lesions was measured by three observers. Interobserver reproducibility was evaluated using intraclass correlation coefficients (ICC). P<0.05 was considered to indicate a significant difference.
  
  
  RESULTS
  Semi-automated volumetric measurements of functional parameters (ADC, AE, and VE) before and after IAT as well as change in tumor ADC, AE, or VE had better interobserver agreement (ICC=0.830-0.974) compared with manual ROI-based axial measurements (ICC=0.157-0.799). Semi-automated measurements of tumor volume and size in the axial plane before and after IAT had better interobserver agreement (ICC=0.854-0.996) compared with manual size measurements (ICC=0.543-0.596), and interobserver agreement for change in tumor RECIST size was also higher using semi-automated measurements (ICC=0.655) compared with manual measurements (ICC=0.169). EASL measurements of tumor enhancement in the axial plane before and after IAT ((ICC=0.758-0.809), and changes in EASL after IAT (ICC=0.653) had good interobserver agreement.
  
  
  CONCLUSIONS
  Semi-automated measurements of functional changes assessed by ADC and VE based on whole-lesion segmentation demonstrated better reproducibility than ROI-based axial measurements, or RECIST or EASL measurements.
authors.affiliation: The Johns Hopkins School of Medicine, Department of Radiology, Baltimore, MD, United States.
authors.forename: David
authors.initials: D
authors.lastname: Bonekamp
authors.affiliation: The Johns Hopkins School of Medicine, Department of Radiology, Baltimore, MD, United States.
authors.forename: Susanne
authors.initials: S
authors.lastname: Bonekamp
authors.affiliation: The Johns Hopkins School of Medicine, Department of Radiology, Baltimore, MD, United States.
authors.forename: Vivek Gowdra
authors.initials: VG
authors.lastname: Halappa
authors.affiliation: The Johns Hopkins School of Medicine, Department of Radiology, Baltimore, MD, United States.
authors.forename: Jean-Francois H
authors.initials: JF
authors.lastname: Geschwind
authors.affiliation: The Johns Hopkins School of Medicine, Department of Radiology, Baltimore, MD, United States.
authors.forename: John
authors.initials: J
authors.lastname: Eng
authors.affiliation: The Johns Hopkins School of Medicine, Department of Radiology, Baltimore, MD, United States.
authors.forename: Celia Pamela
authors.initials: CP
authors.lastname: Corona-Villalobos
authors.affiliation: The Sidney Kimmel Comprehensive Cancer Center, The Johns Hopkins University School of Medicine, Baltimore, MD, United States; The Johns Hopkins School of Medicine, Department of Surgery, Oncology, Baltimore, MD, United States.
authors.forename: Timothy M
authors.initials: TM
authors.lastname: Pawlik
authors.affiliation: The Johns Hopkins School of Medicine, Department of Radiology, Baltimore, MD, United States. Electronic address: ikamel@jhmi.edu.
authors.forename: Ihab R
authors.initials: IR
authors.lastname: Kamel
mesh_terms: D000465:Algorithms; D006528:Carcinoma, Hepatocellular / Q000473:pathology* / Q000628:therapy*; D016461:Chemoembolization, Therapeutic; D005260:Female; D006801:Humans; D007089:Image Enhancement / Q000379:methods; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D021621:Imaging, Three-Dimensional / Q000379:methods; D008113:Liver Neoplasms / Q000473:pathology* / Q000628:therapy*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D015588:Observer Variation; D010363:Pattern Recognition, Automated / Q000379:methods; D015203:Reproducibility of Results; D012189:Retrospective Studies; D012680:Sensitivity and Specificity; D016896:Treatment Outcome; D047368:Tumor Burden
keywords: Cancer treatment response; Functional magnetic resonance imaging; Observer agreement; Reproducibility; Response assessment