Preoperative breast cancer staging: MR imaging of the axilla with ultrasmall superparamagnetic iron oxide enhancement.
OBJECTIVE
To evaluate magnetic resonance (MR) imaging with ultrasmall superparamagnetic iron oxide (USPIO) enhancement for preoperative axillary lymph node staging in patients with breast cancer by using histopathologic findings as the standard of reference.


METHODS
MR imaging was performed with a 1.5-T system within 24-36 hours after the start of intravenous slow-drip infusion of USPIO in 20 patients with breast cancer who were scheduled for surgery, followed by gadolinium-enhanced MR imaging. Lymph nodes were staged prospectively by using newly established criteria, and results were correlated with histologic findings.


RESULTS
In two patients, preoperative findings led to a change in therapeutic approach, and neoadjuvant chemotherapy was given; both patients were excluded from statistical analysis. Results of axillary staging with USPIO-enhanced MR imaging were true-positive in nine, true-negative in seven, false-positive in zero, and false-negative in two of 18 patients (sensitivity, 82%; specificity, 100%; positive predictive value, 100%; second reader, kappa = 1.0). Four hundred five lymph nodes were detected with MR imaging. For first and second readers, respectively, lymph node-based sensitivity was 83% and 73% and specificity was 96% and 97% (kappa = 0.68). USPIO as the intravascular contrast agent could not replace gadolinium for assessment of the primary tumor; however, no clinically relevant interaction was seen. Thus, an integrated imaging approach was feasible in all patients.


CONCLUSIONS
USPIO-enhanced MR imaging has the potential to become an adjunct to conventional MR imaging of the breast for preoperative assessment of axillary lymph nodes in patients with breast cancer.
Michel
Sven C A
SC
Institute of Diagnostic Radiology, University Hospital Zurich, Switzerland.
Keller
Thomas M
TM
Fröhlich
Johannes M
JM
Fink
Daniel
D
Caduff
Rosmarie
R
Seifert
Burkhardt
B
Marincek
Borut
B
Kubik-Huch
Rahel A
RA
D000328:Adult; D000368:Aged; D001365:Axilla; D001943:Breast Neoplasms / Q000188:drug therapy / Q000473:pathology* / Q000601:surgery; D003131:Combined Modality Therapy; D003287:Contrast Media; D003911:Dextrans; D052203:Ferrosoferric Oxide; D006801:Humans; D007501:Iron; D008198:Lymph Nodes / Q000473:pathology*; D008207:Lymphatic Metastasis; D008279:Magnetic Resonance Imaging; D058185:Magnetite Nanoparticles; D008875:Middle Aged; D020360:Neoadjuvant Therapy; D009367:Neoplasm Staging; D010087:Oxides; D011446:Prospective Studies; D016217:Ultrasonography, Mammary
D003287:Contrast Media; D003911:Dextrans; D058185:Magnetite Nanoparticles; D010087:Oxides; C097921:ferumoxtran-10; D007501:Iron; D052203:Ferrosoferric Oxide