title: MDCT necrosis quantification in the assessment of hepatocellular carcinoma response to yttrium 90 radioembolization therapy: comparison of two-dimensional and volumetric techniques.
abstract: OBJECTIVE
  The purpose of this study is to evaluate the reproducibility and agreement of tumor necrosis quantification performed by two-dimensional and volumetric methods in a cohort of patients with hepatocellular carcinoma (HCC) treated with yttrium-90 ((90)Y) radioembolization.
  
  
  METHODS
  Twenty-nine consecutive patients (21 men, 8 women; mean age 66.6 years; age range, 44-90 years) with HCC treated with (90)Y radioembolization that underwent liver multidetector computed tomography (MDCT) were included. Two independent radiologists evaluated the necrosis proportion of the lesions with two-dimensional (2D) measurements according to the European Association for the Study of the Liver guidelines, and with a volumetric method using a voxel-by-voxel analysis. Interobserver reproducibility for each method was assessed by using within-subject coefficients of variation (WSCV), intraclass correlation coefficients (ICC), and Lin's concordance correlation coefficients (LCC). Agreement between both methods was assessed by using the Bland-Altman plot and the paired t-test.
  
  
  RESULTS
  The volumetric method was more reproducible (WSCV = 27.8%; ICC = 0.914; LCC = 0.909) than the 2D (WSCV = 43.8%; ICC = 0.723; LCC = 0.841). There was a significant difference in the mean calculated necrosis proportions based on 2D and volumetric methods (P = .0129).
  
  
  CONCLUSIONS
  Voxel-by-voxel quantification of HCC necrosis is a more reproducible method than 2D analysis.
authors: Department of Radiology, Northwestern Memorial Hospital, Northwestern University-Feinberg School of Medicine, 676 North Saint Clair Street, Suite 800, Chicago, IL 60611, USA.
authors: Mauricio Stanzione
authors: MS
authors: Galizia
authors: Hüseyin Gürkan
authors: HG
authors: Töre
authors: Hamid
authors: H
authors: Chalian
authors: Robert
authors: R
authors: McCarthy
authors: Riad
authors: R
authors: Salem
authors: Vahid
authors: V
authors: Yaghmai
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D006528:Carcinoma, Hepatocellular / Q000000981:diagnostic imaging* / Q000532:radiotherapy*; D005260:Female; D006801:Humans; D021621:Imaging, Three-Dimensional / Q000379:methods*; D008113:Liver Neoplasms / Q000000981:diagnostic imaging* / Q000532:radiotherapy*; D008297:Male; D008875:Middle Aged; D009336:Necrosis / Q000000981:diagnostic imaging; D011856:Radiographic Image Enhancement / Q000379:methods; D011857:Radiographic Image Interpretation, Computer-Assisted / Q000379:methods; D019275:Radiopharmaceuticals / Q000627:therapeutic use; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D014057:Tomography, X-Ray Computed / Q000379:methods*; D016896:Treatment Outcome; D015021:Yttrium Radioisotopes / Q000627:therapeutic use*
chemical_list: D019275:Radiopharmaceuticals; D015021:Yttrium Radioisotopes