title: Evaluation of lymph node metastases: comparison of gadofluorine M-enhanced MRI and diffusion-weighted MRI in a rabbit VX2 rectal cancer model.
abstract: OBJECTIVE
  To compare the diagnostic performance of a diffusion-weighted imaging (DWI) dataset and a gadofluorine M-enhanced imaging dataset for identifying lymph node (LN) metastases in a rabbit rectal cancer model.
  
  
  METHODS
  VX2 carcinomas were injected into the rectum of 26 rabbits. Four weeks later, T2-weighted imaging (T2WI), pre-T1WI, DWI, and post-T1WI were performed. Two radiologists independently reviewed the DWI set (T2WI, pre-T1WI, DWI) and the gadofluorine M set (T2WI, pre- and post-T1WI) and recorded their confidence scores for LN metastasis on a per-LN basis. Receiver operating characteristic (ROC) analysis was performed to compare the area under the ROC curve (A(z) ) of the two imaging sets. Histopathologic results were used as the reference standard.
  
  
  RESULTS
  The A(z) and sensitivity of the gadofluorine M set were comparable to those of the DWI set (A(z) , for reader 1, 0.849, 0.829, P = 0.571; for reader 2, 0.923, 0.876, P = 0.212; sensitivity, for reader 1, 97%, 97%; for reader 2, 97%, 92%, P = 0.304). The specificity of the former was greater than that of the latter (for reader 1, 65%, 53%, P = 0.0003; for reader 2, 81%, 68%, P = 0.01).
  
  
  CONCLUSIONS
  Gadofluorine M-enhanced images provided greater specificity than DWI for identifying LN metastases, whereas the A(z) and sensitivity of the former were comparable to those of the latter.
authors.affiliation: Department of Radiology, Haeundae Paik Hospital, Inje University College of Medicine, Busan, Korea.
authors.forename: Seung Ho
authors.initials: SH
authors.lastname: Kim
authors.forename: Jeong Min
authors.initials: JM
authors.lastname: Lee
authors.forename: Sung Kyoung
authors.initials: SK
authors.lastname: Moon
authors.forename: Yong Eun
authors.initials: YE
authors.lastname: Chung
authors.forename: Jin Ho
authors.initials: JH
authors.lastname: Paik
authors.forename: Seung Hong
authors.initials: SH
authors.lastname: Choi
authors.forename: Min Uk
authors.initials: MU
authors.lastname: Kim
authors.forename: Joon Koo
authors.initials: JK
authors.lastname: Han
authors.forename: Byung Ihn
authors.initials: BI
authors.lastname: Choi
mesh_terms: D000818:Animals; D045744:Cell Line, Tumor; D003287:Contrast Media; D038524:Diffusion Magnetic Resonance Imaging; D004195:Disease Models, Animal; D005466:Fluorocarbons; D007089:Image Enhancement / Q000379:methods*; D008207:Lymphatic Metastasis / Q000175:diagnosis*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D009368:Neoplasm Transplantation; D009374:Neoplasms, Experimental; D009942:Organometallic Compounds; D012372:ROC Curve; D011817:Rabbits; D012004:Rectal Neoplasms / Q000473:pathology*; D012680:Sensitivity and Specificity
chemical_list: D003287:Contrast Media; D005466:Fluorocarbons; D009942:Organometallic Compounds; C517961:gadofluorine M