Purpose:To evaluate the efficacy of the arterial phase of spiral CT in parametrial invasion of uterine cervical carcinoma. Materials and Methods:Two-phase spiral CT images of 22 patients with pathologically proven cervical carcinomas were reteospectively, studied. With regard to the lateral margin of the cervix, eccentrci parametrial soft tissue, parameterial strands and obliteration of periureteral fat, images of the arterial phase were compared by three radiologists with those of the late phase. Results:Five of 15 surgically-proven cervical cancers with no parametrial involvement (33%) showed parametrial strands or eccentric soft tissue lesion in the late phase. Four of the five patients (80%) showed early vascular enhancement of the linear strands or eccentric soft tissur mass in the arterial, phase and bacause of this additional scan, correct diagnosis was possible. Six of seven cases of invasive carvical cancer(85.7%) showed linear strands in the late phase but two patients showed partial vascular enhancement of the parameterial strands and correct diagnosis was therefore possible. For the evaluation of the lateral margin of the cervix(4/7, 57.1%) and periureteral fat obliteration(3/7, 42.9%), images of the late phase were superior to those of the arterial phase. Conclusion:In uterine cervical carcinoma, the late phase of conventional CT is normally used to identify vascular structures as false-positive parameterial strands;the arterial phase of spiral CT is, however, superior.