title: TCL-SPION-enhanced MRI for the detection of lymph node metastasis in murine experimental model.
abstract: OBJECTIVE
  The aim of this study was to assess the feasibility of thermally cross-linked superparamagnetic iron oxide nanoparticle contrast (TCL-SPION) in magnetic resonance (MR) imaging (MRI) for the detection of lymph node metastasis in experimental model.
  
  
  METHODS
  B16F1 human melanoma cells were subcutaneously injected into the thighs of C57BL/6 mice (n = 10). MRI was performed 21 days after tumor injection using a 4.7-T MR scanner. In vivo MRI was performed before and after the intravenous administration of TCL-SPION using T2 fast spin-echo and T2 gradient-echo pulse sequences. Then, ex vivo MR images were obtained for resected inguinal lymph nodes (n = 18) using the same pulse sequences as for in vivo imaging. On the basis of hematoxylin and eosin staining results, the lymph nodes were classified into three groups: group 1, nonmetastatic; group 2, tumor volume <50% of the resected sample; and group 3, tumor volume >50% of the resected sample. Size, signal-to-background ratio, and enhancement pattern were evaluated in each of the three groups on ex vivo images.
  
  
  RESULTS
  The findings observed on ex vivo MR images of 18 inguinal lymph nodes were compared with histopathologic findings. All nodes were classified into three groups: group 1, n = 6; group 2, n = 5; and group 3, n = 7. The sizes of the lymph nodes in group 1 were significantly different from the sizes of those in group 3 (P = .014), but there was no significant difference in lymph node sizes between groups 1 and 2 (P = .792). Signal-to-background ratios of samples in groups 2 and 3 were significantly higher than those of samples in group 1 (P = .045 and P = .007, respectively). Each group of lymph nodes showed characteristic enhancement patterns that were well correlated between the images and pathology, except for one node.
  
  
  CONCLUSIONS
  The features and extent of metastasis in the lymph nodes corresponded to those observed on TCL-SPION-enhanced MR images. TCL-SPION-enhanced MRI is useful for the detection and estimation of lymph node metastasis.
authors.affiliation: Department of Radiology, Institute for Radiological Imaging Science, Wonkwang University School of Medicine, Shinyong-dong, Iksan, Jeonbuk, Korea.
authors.forename: Se-Woong
authors.initials: SW
authors.lastname: Lim
authors.forename: Hye-Won
authors.initials: HW
authors.lastname: Kim
authors.forename: Hong-Yeoung
authors.initials: HY
authors.lastname: Jun
authors.forename: Seong-Hoon
authors.initials: SH
authors.lastname: Park
authors.forename: Kwon-Ha
authors.initials: KH
authors.lastname: Yoon
authors.forename: Hun-Soo
authors.initials: HS
authors.lastname: Kim
authors.forename: Sangyong
authors.initials: S
authors.lastname: Jon
authors.forename: Mi Kyung
authors.initials: MK
authors.lastname: Yu
authors.forename: Seon-Kwan
authors.initials: SK
authors.lastname: Juhng
mesh_terms: D000818:Animals; D045744:Cell Line, Tumor; D003287:Contrast Media; D003911:Dextrans; D004195:Disease Models, Animal; D006801:Humans; D007089:Image Enhancement / Q000379:methods*; D008198:Lymph Nodes / Q000473:pathology*; D008207:Lymphatic Metastasis; D008279:Magnetic Resonance Imaging / Q000379:methods*; D058185:Magnetite Nanoparticles; D008545:Melanoma / Q000473:pathology* / Q000556:secondary*; D051379:Mice; D008810:Mice, Inbred C57BL
chemical_list: D003287:Contrast Media; D003911:Dextrans; D058185:Magnetite Nanoparticles; C097921:ferumoxtran-10