Posterior-Anterior Projection of Pelvic Radiographs in Children Meets the Correct Positioning Criteria

Abstract

Background: There are many studies suggesting that the pelvic radiographs taken in posterior-anterior (PA) projection cause far less radiation exposure than anterior-posterior (AP) projection. However, PA projection is rarely used in daily practice due to the concern that the obtained images will not provide radiological standards. Objectives: The aim of the study was to determine whether PA projections meet the radiological criteria of correct positioning as AP projections. Patients and Methods: In this prospective study, radiographs of 160 patients (80 PA and 80 AP images) were obtained randomly. Pelvic rotation index (PRI), symphysis ischium angle (SIA) and pelvic inclination index (PII) were used to evaluate whether the pelvic radiographs were suitable for radiological assessment. Results: The reliability of AP and PA projections was excellent for PRI (Intraclass correlation coefficient [ICC] = 0.66, 95% confidence interval [CI] = 0.90 - 0.98), SIA (ICC = 0.99, 95% CI = 0.90 - 0.98), and PII (ICC = 0.95, 95% CI = 0.90 - 0.98). Conclusion: PA projection instead of AP projection for pelvic radiography has no drawback in terms of acceptability criteria. Considering PA projection is a dose reducing technique requiring no additional equipment, it may be a safer option for children.