The aim of this study was to assess nodal enhancement with
ultrasmall superparamagnetic iron oxide (
USPIO)-enhanced magnetic resonance imaging (MRI) during preoperative staging of gynecological pelvic
tumors within the same imaging session for the primary
tumor. Pelvic MRI was performed 18-28 h after
intravenous infusion of
USPIO (
Combidex/
Sinerem, 2.6 mg Fe/kg
body weight) in 13 women (mean age 51 years) scheduled for surgery for biopsy proven ( n=11) or clinically suspected ( n=2) uterine
carcinoma. Axial T1-weighted spin-echo (SE), T2-weighted fast SE (FSE; with fat saturation), fast spoiled gradient-recalled (FSPGR) echo, sagittal and oblique T2-weighted FSE sequences were acquired on a 1.5-T system. Lymph nodes were prospectively staged using standard criteria, i.e., size and shape, as well as
USPIO enhancement. Results were correlated with histology findings. MRI correctly staged all primary uterine
tumors. In one case, the preoperative diagnosis of stage IV switched the therapeutic approach to
radiochemotherapy. Ninety-one (86 benign, 5 malignant) of the histologically characterized nodes could be correlated with their MRI counterparts. One node was false positive; three
micrometastases greater than 5 mm and one 5-mm
metastasis were missed. On a nodal basis, the sensitivity score was 0.33 and the specificity score, 0.99. On a patient basis, the sensitivity score was 0.25 and the specificity score, 0.80. Our preliminary results indicate that
USPIO-enhanced pelvic MRI for preoperative nodal assessment is feasible within one imaging session for primary
tumors and that it has a high specificity. However, the low sensitivity in the present study is a limitation for the clinical application of this technique.