Metastatic lymph nodes in patients with cervical cancer:: Detection with MR imaging and FDG PET

PURPOSE: To compare the diagnostic accuracy of magnetic resonance (MR) imaging with that of positron emission tomography (PET) with 2-[fluorine 18]fluoro2-deoxy-D-glucose (FDG) for detecting metastatic lymph nodes in patients with cervical cancer. MATERIALS AND METHODS: Before radical hysterectomy and pelvic lymphadenectomy in 35 patients with International Federation of Gynecology and Obstetrics stage IB or II cervical cancer, abdominal FDG-PET and MR imaging were performed. Malignancy criteria were a lymph node diameter of 1 cm or more at MR imaging and a focally increased FDG uptake at PET. The findings of FDG-PET and MR imaging were compared with histologic findings. RESULTS: Histologic examination revealed pN0-stage cancer in 24 patients and pN1-stage cancer in 11 patients. On a patient basis, node staging resulted in sensitivities of 0.91 with FDG-PET and 0.73 with MR imaging and specificities of 1.00 with FDG-PET and 0.83 with MR imaging. The positive predictive value (PPV) of FDG-PET was 1.00 and that of MR imaging, 0.67 (not significant). The metastatic involvement of lymph node sites was identified at FDG-PET with a PPV of 0.90; at MR imaging, 0.64 (P <.05, Fisher exact test). CONCLUSION: Metabolic imaging with FDG-PET is an alternative to morphologic MR imaging for detecting metastatic lymph nodes in patients with cervical cancer.