title: Superparamagnetic iron oxide-enhanced MRI at 3 T for accurate axillary staging in breast cancer.
abstract: BACKGROUND
  The aim of this study was to evaluate whether MRI at 3 T with superparamagnetic iron oxide (SPIO) enhancement is an accurate and useful method for detecting metastases in sentinel nodes identified by CT-lymphography (CT-LG) in patients with breast cancer. The results were compared with those obtained using CT-LG alone and diagnosing metastasis according to size criteria.
  
  
  METHODS
  Patients with clinically node-negative breast cancer were included. Sentinel nodes identified by CT-LG were evaluated prospectively using SPIO-enhanced MRI at 3 T. Sentinel node size was measured on CT-LG, and a node larger than 5 mm in short-axis diameter was considered metastatic. Sentinel nodes localized by CT-LG were removed, and imaging results and histopathological findings were compared.
  
  
  RESULTS
  Sentinel nodes were identified successfully by CT-LG in 69 (99 per cent) of 70 patients. All 19 patients with a finding of metastasis in sentinel nodes at pathology were also shown to have metastases on MRI. Forty-eight of 50 patients with non-metastatic sentinel nodes diagnosed at pathology were classified as having non-metastatic nodes on MRI. On a patient-by-patient basis, the sensitivity, specificity and accuracy of MRI for the diagnosis of sentinel node metastases were 100, 96 and 97 per cent; respective values for CT-LG were 79, 56 and 62 per cent. The specificity and accuracy of MRI were superior to those of CT-LG (P < 0·001 and P = 0·002 respectively).
  
  
  CONCLUSIONS
  SPIO-enhanced MRI at 3 T is useful for accurate diagnosis of metastatic sentinel nodes, indicating that sentinel node biopsy may be avoided in patients with breast cancer who have non-metastatic sentinel nodes on imaging.
authors.affiliation: Departments of Breast and Endocrine Surgery, Osaka Medical Centre for Cancer and Cardiovascular Diseases, Osaka, Japan.
authors.forename: K
authors.initials: K
authors.lastname: Motomura
authors.affiliation: Departments of Radiology, Osaka Medical Centre for Cancer and Cardiovascular Diseases, Osaka, Japan.
authors.forename: T
authors.initials: T
authors.lastname: Izumi
authors.affiliation: Departments of Radiology, Osaka Medical Centre for Cancer and Cardiovascular Diseases, Osaka, Japan.
authors.forename: S
authors.initials: S
authors.lastname: Tateishi
authors.affiliation: Departments of Breast and Endocrine Surgery, Osaka Medical Centre for Cancer and Cardiovascular Diseases, Osaka, Japan.
authors.forename: Y
authors.initials: Y
authors.lastname: Tamaki
authors.affiliation: Centre for Cancer Control and Statistics, Osaka Medical Centre for Cancer and Cardiovascular Diseases, Osaka, Japan.
authors.forename: Y
authors.initials: Y
authors.lastname: Ito
authors.affiliation: Departments of Radiology, Osaka Medical Centre for Cancer and Cardiovascular Diseases, Osaka, Japan.
authors.forename: T
authors.initials: T
authors.lastname: Horinouchi
authors.affiliation: Departments of Radiology, Osaka Medical Centre for Cancer and Cardiovascular Diseases, Osaka, Japan.
authors.forename: K
authors.initials: K
authors.lastname: Nakanishi
mesh_terms: D000328:Adult; D000368:Aged; D001365:Axilla; D001943:Breast Neoplasms / Q000000981:diagnostic imaging / Q000473:pathology*; D018270:Carcinoma, Ductal, Breast / Q000000981:diagnostic imaging / Q000473:pathology; D002285:Carcinoma, Intraductal, Noninfiltrating / Q000000981:diagnostic imaging / Q000473:pathology; D018275:Carcinoma, Lobular / Q000000981:diagnostic imaging / Q000473:pathology; D003287:Contrast Media; D005260:Female; D005290:Ferric Compounds; D006801:Humans; D008198:Lymph Nodes / Q000000981:diagnostic imaging / Q000473:pathology*; D008207:Lymphatic Metastasis; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008875:Middle Aged; D009367:Neoplasm Staging; D011446:Prospective Studies; D012680:Sensitivity and Specificity; D014057:Tomography, X-Ray Computed
chemical_list: D003287:Contrast Media; D005290:Ferric Compounds; C000499:ferric oxide