title: Texture analysis of (125)I-A5B7 anti-CEA antibody SPECT differentiates metastatic colorectal cancer model phenotypes and anti-vascular therapy response.
abstract: BACKGROUND
  We aimed to test the ability of texture analysis to differentiate the spatial heterogeneity of (125)I-A5B7 anti-carcinoembryonic antigen antibody distribution by nano-single photon emission computed tomography (SPECT) in well-differentiated (SW1222) and poorly differentiated (LS174T) hepatic metastatic colorectal cancer models before and after combretastatin A1 di-phosphate anti-vascular therapy.
  
  
  METHODS
  Nano-SPECT imaging was performed following tail vein injection of 20 MBq (125)I-A5B7 in control CD1 nude mice (LS174T, n=3 and SW1222, n=4), and CA1P-treated mice (LS174T, n=3; SW1222, n=4) with liver metastases. Grey-level co-occurrence matrix textural features (uniformity, homogeneity, entropy and contrast) were calculated in up to three liver metastases in 14 mice from control and treatment groups.
  
  
  RESULTS
  Before treatment, the LS174T metastases (n=7) were more heterogeneous than SW1222 metastases (n=12) (uniformity, P=0.028; homogeneity, P=0.01; contrast, P=0.045). Following CA1P, LS174T metastases (n=8) showed less heterogeneity than untreated LS174T controls (uniformity, P=0.021; entropy, P=0.006). Combretastatin A1 di-phosphate-treated SW1222 metastases (n=11) showed no difference in texture features compared with controls (all P>0.05).
  
  
  CONCLUSIONS
  Supporting the potential for novel imaging biomarkers, texture analysis of (125)I-A5B7 SPECT shows differences in spatial heterogeneity of antibody distribution between well-differentiated (SW1222) and poorly differentiated (LS174T) liver metastases before treatment. Following anti-vascular treatment, LS174T metastases, but not SW1222 metastases, were less heterogeneous.
authors.affiliation: UCL Cancer Institute, University College London, 72 Huntley St, London WC1E 6BT UK.
authors.forename: V
authors.initials: V
authors.lastname: Rajkumar
authors.affiliation: Division of Imaging Sciences and Biomedical Engineering, Kings College London, St Thomas' Hospital, Westminster Bridge Road, London SE1 7EH, UK.
authors.forename: V
authors.initials: V
authors.lastname: Goh
authors.affiliation: Division of Imaging Sciences and Biomedical Engineering, Kings College London, St Thomas' Hospital, Westminster Bridge Road, London SE1 7EH, UK.
authors.forename: M
authors.initials: M
authors.lastname: Siddique
authors.affiliation: UCL Cancer Institute, University College London, 72 Huntley St, London WC1E 6BT UK.
authors.forename: M
authors.initials: M
authors.lastname: Robson
authors.affiliation: UCL Cancer Institute, University College London, 72 Huntley St, London WC1E 6BT UK.
authors.forename: G
authors.initials: G
authors.lastname: Boxer
authors.affiliation: UCL Cancer Institute, University College London, 72 Huntley St, London WC1E 6BT UK.
authors.forename: R B
authors.initials: RB
authors.lastname: Pedley
authors.affiliation: Division of Imaging Sciences and Biomedical Engineering, Kings College London, St Thomas' Hospital, Westminster Bridge Road, London SE1 7EH, UK.
authors.forename: G J R
authors.initials: GJ
authors.lastname: Cook
mesh_terms: D020533:Angiogenesis Inhibitors / Q000494:pharmacology; D000818:Animals; D000911:Antibodies, Monoclonal; D002272:Carcinoembryonic Antigen / Q000096:biosynthesis / Q000276:immunology; D045744:Cell Line, Tumor; D015179:Colorectal Neoplasms / Q000098:blood supply / Q000000981:diagnostic imaging* / Q000188:drug therapy* / Q000473:pathology; D011756:Diphosphates / Q000494:pharmacology*; D005260:Female; D064593:Heterografts; D006801:Humans; D007457:Iodine Radioisotopes; D008113:Liver Neoplasms / Q000098:blood supply / Q000000981:diagnostic imaging* / Q000188:drug therapy / Q000556:secondary*; D051379:Mice; D008819:Mice, Nude; D009362:Neoplasm Metastasis; D010641:Phenotype; D019275:Radiopharmaceuticals; D013267:Stilbenes / Q000494:pharmacology*; D015899:Tomography, Emission-Computed, Single-Photon / Q000379:methods
chemical_list: C518613:A5B7 monoclonal antibody; D020533:Angiogenesis Inhibitors; D000911:Antibodies, Monoclonal; D002272:Carcinoembryonic Antigen; D011756:Diphosphates; D007457:Iodine Radioisotopes; C465018:Oxi 4503; D019275:Radiopharmaceuticals; D013267:Stilbenes