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]fluoro-2-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.