Điều này mang lại một giá trị tích cực tiên đoán của 94% và một giá trị âm định chắc 98,3%. Những dữ liệu này là tương tự khác, truy, đánh giá CT ở trẻ em (45,61), và tương quan với một nghiên cứu tiềm năng nonconsecutive CT (60). | 464 . Blackmore et al. lence of appendicitis identified by pathologic examination following surgery or clinical follow-up was 25 . The diagnostic sensitivity of attending physicians was 95 and the specificity was 98 . This yielded a positive predictive value of 94 and a negative predicative value of . These data are similar to other retrospective evaluations of CT in the pediatric population 45 61 and correlate with a nonconsecutive prospective study of CT 60 . However the limited number of children in this trial and the lack of a direct comparison to graded compression ultrasound preclude definitive comparison of CT versus ultrasound as the primary imaging exam in the pediatric population. The desire to increase the accuracy of imaging yet limit the radiation exposure has led investigators to examine combinations of CT and graded compression ultrasound exam. Two prospective studies examined the combination of graded compression ultrasound as the initial imaging followed by CT study if the ultrasound exam was equivocal or failed to match the clinical presentation 62 63 . Another randomized trial compared CT and ultrasound versus ultrasound alone in a pediatric population 59 . These trials enrolled 585 patients and had a prevalence of appendicitis ranging from 23 to 43 with a pooled prevalence of 39 . The sensitivity of these protocols varied from 77 to 97 with a pooled sensitivity of 95 95 CI 83-100 . The range of specificity was 89 to 99 with a pooled result of 93 95 CI 87-97 . As would be expected these protocols demonstrated a greater sensitivity when the combined ultrasound followed by CT test results were considered than when the same series of ultrasound data was considered alone. This increased sensitivity however was achieved with the drawback of a lower overall specificity. The single randomized trial demonstrated similar results with CT and ultrasound combined demonstrating a higher sensitivity than ultrasound alone however the sensitivities of .
