Agreement of two-dimensional and three-dimensional transvaginal ultrasound with magnetic resonance imaging with regard to parametrial infiltration in cervical cancer.

Objectives: To compare two-dimensional (2D) and three-dimensional (3D) transvaginal ultrasound with magnetic resonance imaging (MRI) as gold standard in the assessment of parametrial infiltration of cervical cancer, and to determine if all parts of the cervix are equally assessable with ultrasound. Methods: Patients with histologically confirmed macroscopically evident cervical cancer were staged using FIGO criteria and underwent MRI, 2D- and 3D-ultrasound before treatment. When assessing parametrial infiltration with 3D-ultrasound and MRI, the cervix was (virtually) divided into three cylinders of equal size (cranial, middle, caudal) and each cylinder into six sectors in a clockwise manner following a consensus between radiologists and ultrasound examiners. The presence and the extent of parametrial invasion were recorded for each sector. The results for 2D-ultrasound, 3Dultrasound and MRI were compared, results being reported as percentage agreement and Kappa value. Results: 29 consecutive patients were included. The percentage agreement between 2D-ultrasound and MRI in assessing parametrial infiltration (yes or no) was 76% (kappa 0.459), that between 3Dultrasound and MRI 79% (kappa 0.508). 2D-ultrasound showed the following agreement with MRI: 90% for the ventral parametria (kappa 0.720), 72% for the right lateral parametrium (kappa 0.494), 69% for the left lateral parametrium (kappa 0.412), 58.5% for the dorsal parametria (kappa 0.017). 3D-ultrasound showed the following agreement with MRI: 62.5% for the ventral parametria (kappa 0.176), 81% for the right lateral parametrium (kappa 0.595), 70% for the left lateral parametrium (kappa 0.326), 52% for the dorsal parametria (kappa 0.132). The best agreement between 3Dultrasound and MRI was obtained for the middle cervical cylinder (agreement 76%, kappa 0.438) and the poorest agreement for the caudal cylinder (agreement 34.5%, kappa 0.125). Conclusion: 2D- and 3D-ultrasound showed similar moderate agreement with MRI. 2D- and 3Dultrasound are cheaper and more easily available than MRI and should be considered in the preoperative work-up of cervical cancer.