CT of the normal and abnormal parametria in cervical cancer.

To evaluate CT criteria for differentiating a cervical cancer confined to the cervix from a lesion that invades the parametria, 16 patients with newly diagnosed, untreated cervical cancer were studied with CT. Twenty-five parametria were confirmed by radical hysterectomy, transvaginal parametrial fine-needle aspiration cytology, or excretory urography. In eight tumor-free parametria, CT findings indicating confined tumor were: (1) smooth, well defined cervical margins; (2) lack of prominent parametrial soft-tissue strands; (3) no parametrial soft-tissue mass; and (4) preservation of the periureteral fat plane. The simultaneous occurrence of these four findings was seen in six of eight tumor-free parametria and in no tumor-infiltrated parametria. In 17 tumor-positive parametria, CT findings associated with parametrial tumor invasion were: (1) irregularity or poor definition of the lateral cervical margins; (2) prominent parametrial soft-tissue strands; (3) obliteration of the periureteral fat plane; and (4) an eccentric parametrial soft-tissue mass. The latter two findings were seen only in tumor-positive parametria. Irregularity of the cervical margins and prominent parametrial strands were seen most commonly with parametrial tumor invasion, but were also occasionally seen with parametrial inflammation. On the basis of the criteria developed in this report, CT may be used as an adjunct to the physical examination in differentiating stage I cervical cancer from more advanced disease in selected patients.