title: Potential role of combined FDG PET/CT & contrast enhancement MRI in a rectal carcinoma model with nodal metastases characterized by a poor FDG-avidity.
abstract: OBJECTIVE
  To investigate the additional role of MRI contrast enhancement (CE) in the primary tumor and the FDG uptake at PET in the lymph-node metastases.
  
  
  METHODS
  A model of colorectal cancer induced by orthotopic HT-29 cells microinjection, producing pelvic lymph node metastases, was assessed using CE-MRI and FDG-PET. Histology and GLUT-1 immunohistochemistry were performed on primary tumors and iliac lymph nodes.
  
  
  RESULTS
  Primary tumors were characterized by low FDG-uptake but high CE-MRI, particularly at tumor periphery. Undetectable FDG-uptake characterized the metastatic lymph-nodes. Histology revealed large stromal bundles at tumor periphery and a dense network of stromal fibers and neoplastic cells in the inner portion of the tumors. Both primary tumors and positive lymph nodes showed poor GLUT-1 staining.
  
  
  CONCLUSIONS
  Our data support the complementary role of MRI-CE and FDG PET in some types of carcinomas characterized by abundant cancer-associated stroma and poor FDG avidity consequent to poor GLUT-1 transported. In these tumors FDG-PET alone may be not completely adequate to obtain an adequate tumor radiotherapy planning, and a combination with dual CE-MRI is strongly recommended.
authors.affiliation: Department of Morphological-Biomedical Sciences, Section of Anatomy and Histology, University of Verona, Verona, Italy.
authors.forename: Paolo
authors.initials: P
authors.lastname: Farace
authors.forename: Giamaica
authors.initials: G
authors.lastname: Conti
authors.forename: Flavia
authors.initials: F
authors.lastname: Merigo
authors.forename: Stefano
authors.initials: S
authors.lastname: Tambalo
authors.forename: Pasquina
authors.initials: P
authors.lastname: Marzola
authors.forename: Andrea
authors.initials: A
authors.lastname: Sbarbati
authors.forename: Carmelo
authors.initials: C
authors.lastname: Quarta
authors.forename: Daniela
authors.initials: D
authors.lastname: D'Ambrosio
authors.forename: Sotirios
authors.initials: S
authors.lastname: Chondrogiannis
authors.forename: Cristina
authors.initials: C
authors.lastname: Nanni
authors.forename: Domenico
authors.initials: D
authors.lastname: Rubello
mesh_terms: D000230:Adenocarcinoma / Q000175:diagnosis* / Q000556:secondary*; D000818:Animals; D003287:Contrast Media; D019788:Fluorodeoxyglucose F18; D019073:HT29 Cells; D006801:Humans; D007089:Image Enhancement / Q000379:methods*; D008207:Lymphatic Metastasis; D008279:Magnetic Resonance Imaging / Q000379:methods*; D051379:Mice; D008819:Mice, Nude; D012004:Rectal Neoplasms / Q000175:diagnosis*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013382:Subtraction Technique; D014057:Tomography, X-Ray Computed / Q000379:methods*
chemical_list: D003287:Contrast Media; D019788:Fluorodeoxyglucose F18