title: Diffusion weighted images of metastatic as compared with nonmetastatic axillary lymph nodes in patients with newly diagnosed breast cancer.
abstract: BACKGROUND
  To investigate the ability of diffusion weighted images (DWI) to differentiate between metastatic and nonmetastatic axillary lymph nodes (LNs) in patients with newly diagnosed breast cancer.
  
  
  METHODS
  From January 2010 to February 2012, DWI was performed at b values of 0 and 800 for 16 metastatic LNs from 16 patients with breast cancer, and 20 nonmetastatic LNs from 20 women without breast cancer. The metastatic LNs were proven by ultrasound (US) guided core biopsy and the same LNs were identified on MRI by comparing the US images with MR images. Nonmetastatic LNs were verified by the stability in size and shape for at least 2 years on MRI. The apparent diffusion coefficient (ADC) value of the metastatic and nonmetastatic axillary LNs was compared. Receiver-operating-characteristics (ROC) analysis was performed to evaluate the diagnostic performance of the ADC value in differentiating between metastatic and nonmetastatic axillary LNs.
  
  
  RESULTS
  The mean ADC value was 0.746 × 10(-3) for metastatic LNs and 1.033 × 10(-3) for nonmetastatic LNs (P < 0.001). The area under the ROC curve was 0.884. The sensitivity and specificity for differentiating metastatic from nonmetastatic axillary LNs using a cutoff ADC value of 0.852 were 85% and 81%, respectively.
  
  
  CONCLUSIONS
  There is a statistically significant difference between the ADC values of pathologically proven metastatic LNs and nonmetastatic LNs. DWI and ADC values are a useful tool for differentiating metastatic from nonmetastatic axillary LNs.
authors.affiliation: Department of Radiology, Faculty of Medicine, Saga University, Saga, Japan.|Department of Radiology, University of Chicago, Chicago, Illinois, USA.
authors.forename: Ken
authors.initials: K
authors.lastname: Yamaguchi
authors.affiliation: Department of Radiology, University of Chicago, Chicago, Illinois, USA.
authors.forename: David
authors.initials: D
authors.lastname: Schacht
authors.affiliation: Department of Radiology, Faculty of Medicine, Saga University, Saga, Japan.
authors.forename: Takahiko
authors.initials: T
authors.lastname: Nakazono
authors.affiliation: Department of Radiology, Faculty of Medicine, Saga University, Saga, Japan.
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Irie
authors.affiliation: Department of Radiology, University of Chicago, Chicago, Illinois, USA.
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Abe
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001365:Axilla / Q000473:pathology*; D001706:Biopsy; D001943:Breast Neoplasms / Q000175:diagnosis* / Q000473:pathology*; D038524:Diffusion Magnetic Resonance Imaging; D005260:Female; D006801:Humans; D008198:Lymph Nodes / Q000473:pathology*; D008207:Lymphatic Metastasis; D008875:Middle Aged; D012372:ROC Curve; D012680:Sensitivity and Specificity
keywords: apparent diffusion coefficient; axillary lymph node; breast cancer; diffusion weighted image; lymph node metastasis