title: CT textural analysis of hepatic metastatic colorectal cancer: pre-treatment tumor heterogeneity correlates with pathology and clinical outcomes.
abstract: OBJECTIVE
  The purpose of the study was to determine if CT texture features of untreated hepatic metastatic colorectal cancer (CRC) relate to pathologic features and clinical outcomes.
  
  
  METHODS
  Tumor texture analysis was performed on single hepatic metastatic lesions on pre-treatment contrast-enhanced CT scans in 77 pts (mean age 58, 34F/43M) using a novel tool. Measures of heterogeneity, including entropy, kurtosis, skewness, mean, mean positive pixels (MPP), and standard deviation (SD) of pixel distribution histogram were derived with filter values corresponding to fine (spatial scaling factor (ssf) 2), medium (ssf 3, 4), and coarse textures (ssf 5, 6). Texture parameters were correlated with tumor grade, baseline serum CEA, and KRAS mutation status. Overall survival was also correlated using Cox proportional hazards models. Single-slice 2D vs. whole-tumor volumetric 3D texture analysis was compared in a subcohort of 20 patients.
  
  
  RESULTS
  Entropy, MPP, and SD at medium filtration levels were significantly associated with tumor grade (MPP ssf 3 P = 0.002, SD ssf 3 P = 0.004, entropy ssf 4 P = 0.007). Skewness was negatively associated KRAS mutation (P = 0.02). Entropy at coarse filtration levels was associated with survival (Hazard ratio (HR) for death 0.65, 95% CI 0.44-0.95, P = 0.03). Texture results for 2D and 3D analysis were similar.
  
  
  CONCLUSIONS
  CT texture features, particularly entropy, MPP, and SD, are significantly associated with tumor grade in untreated CRC liver metastases. Tumor entropy at coarse filters correlates with overall survival. Single-slice 2D texture analysis appears to be adequate.
authors.affiliation: Department of Radiology, University of Wisconsin School of Medicine and Public Health, E3/311 Clinical Sciences Center, 600 Highland Ave, Madison, WI, 53792, USA. mlubner@uwhealth.org.
authors.forename: Meghan G
authors.initials: MG
authors.lastname: Lubner
authors.affiliation: Department of Radiology, University of Wisconsin School of Medicine and Public Health, E3/311 Clinical Sciences Center, 600 Highland Ave, Madison, WI, 53792, USA.
authors.forename: Nicholas
authors.initials: N
authors.lastname: Stabo
authors.affiliation: Department of Internal Medicine (Sections Human Oncology and Gastroenterology), University of Wisconsin School of Medicine and Public Health, Madison, WI, USA.
authors.forename: Sam J
authors.initials: SJ
authors.lastname: Lubner
authors.affiliation: Department of Radiology, University of Wisconsin School of Medicine and Public Health, E3/311 Clinical Sciences Center, 600 Highland Ave, Madison, WI, 53792, USA.|Department of Medical Physics, University of Wisconsin School of Medicine and Public Health, Madison, WI, USA.
authors.forename: Alejandro Munoz
authors.initials: AM
authors.lastname: del Rio
authors.affiliation: Department of Medical Physics, University of Wisconsin School of Medicine and Public Health, Madison, WI, USA.
authors.forename: Chihwa
authors.initials: C
authors.lastname: Song
authors.affiliation: Department of Internal Medicine (Sections Human Oncology and Gastroenterology), University of Wisconsin School of Medicine and Public Health, Madison, WI, USA.
authors.forename: Richard B
authors.initials: RB
authors.lastname: Halberg
authors.affiliation: Department of Radiology, University of Wisconsin School of Medicine and Public Health, E3/311 Clinical Sciences Center, 600 Highland Ave, Madison, WI, 53792, USA.
authors.forename: Perry J
authors.initials: PJ
authors.lastname: Pickhardt
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015179:Colorectal Neoplasms / Q000473:pathology*; D003287:Contrast Media; D005260:Female; D006801:Humans; D008099:Liver / Q000000981:diagnostic imaging; D008113:Liver Neoplasms / Q000000981:diagnostic imaging* / Q000556:secondary*; D008297:Male; D008875:Middle Aged; D011856:Radiographic Image Enhancement; D015203:Reproducibility of Results; D014057:Tomography, X-Ray Computed
chemical_list: D003287:Contrast Media
keywords: CT; Colorectal cancer; Heterogeneity; Metastases; Texture