Patterns of uterine enhancement with helical CT

Objective: The purpose of this study was to evaluate the enhancement charac teristics of the normal uterine body and cervix using dynamic contrast-enha nced helical CT. Methods: Thirty-eight women scheduled for pelvic CT for no n-gynecologic malignancies underwent dynamic contrast-enhanced helical CT o f the pelvis. Data acquisition was during the arterial phase (30-45 s after the start of injection), the parenchymal phase (90-120 s after the start o f injection), and delayed phase (3-9 min after the start of injection). The images were evaluated by four radiologists for the pattern of myometrial a nd cervical enhancement. Correlation was made with the age and menstrual st atus of the patients. Results: In the uterine body, three types of enhancem ent were observed. Type 1 enhancement, seen in 16 patients (42%), was chara cterized by the visualization of a subendometrial zone of enhancement, 30-1 20 s after the start of injection. Eight of these patients also showed an e nhancing zone in the outer myometrium. Both zones were transitory, and in a ll cases, the uterus became homogeneous in the delayed phase. This pattern was seen predominantly in premenopausal women with a mean age of 34 years. Type 2 enhancement, seen in 17 cases (45%), was defined by the absence of s ubendometrial enhancement in the early phase. Enhancement was either diffus e from the outset or originated in the outer myometrium. This pattern was s een nearly equally in premenopausal and postmenopausal women with a mean ag e of 40 years. Type 3 enhancement was seen in five postmenopausal patients (13%) with a mean age of 53 years and was characterized by faint diffuse en hancement. In the cervix, a zonal pattern of enhancement defining inner and outer stroma was seen in 23 patients (61%). Fifteen patients were premenop ausal and eight were postmenopausal. Conclusion: In this study, we have sho wn a transitory zonal distribution of the contrast in the myometrium and ce rvix using dynamic contrast-enhanced helical CT. The demonstration of these patterns is not constant and depends on individual variables. Of these, th e menopausal status and/or age of the patient appear to be most important. While CT:is not the primary imaging modality to evaluate the uterus, knowle dge of these normal findings might help when confronted with unusual uterin e enhancement during routine studies obtained with spiral CT. (C) 1998 Else vier Science Ireland Ltd. All rights reserved.