XÁC ĐỊNH GÓC CHỤP X-QUANG INLET VÀ OUTLET TỐI ƯU DỰA TRÊN HÌNH ẢNH CẮT LỚP VI TÍNH VÙNG CHẬU TẠI BỆNH VIỆN ĐA KHOA HÙNG VƯƠNG NĂM 2025

Abstract

Background: Traditional pelvic inlet and outlet radiographs are typically performed at 45° angulation. Recent international studies have shown substantial ethnic variation in optimal angles, which often deviate from 45°. Domestic data on optimal angles remain limited.

Objectives: To determine the optimal inlet and outlet radiographic angles in adults in the study sample at Hung Vuong General Hospital using multiplanar reconstructed CT, and to assess differences by sex, age group, and body mass index (BMI).

Methods: This retrospective cross-sectional study included 163 adults (≥18 years) who underwent abdominopelvic CT from July to December 2025 at Hung Vuong General Hospital and its satellite clinics. Patients with pelvic fractures, prior pelvic surgery, congenital deformities, or structural pelvic abnormalities were excluded. Angles were measured independently on sagittal multiplanar reconstructions by two experienced radiologic technologists. Inter-observer and intra-observer reliability were assessed using the intraclass correlation coefficient (ICC). Statistical analysis used SPSS v26.0 (p < 0.05). The study was approved by the hospital ethics committee.

Results: The mean optimal inlet angle was 32.04° ± 2.04° (95% CI: 31.73–32.35). The mean optimal outlet angle was 55.21° ± 1.81° (95% CI: 54.93–55.49). Measurement reliability was excellent: inter-observer ICC for inlet = 0.94 (95% CI: 0.92–0.96) and for outlet = 0.93 (95% CI: 0.91–0.95); intra-observer ICCs were 0.96 and 0.95, respectively (all p < 0.001). No statistically significant differences were observed by sex, age group, or BMI category (all p > 0.05). The obese group was very small (n = 4), limiting power to detect differences.

Conclusions: In this study sample at Hung Vuong General Hospital, optimal pelvic inlet and outlet radiographic angles were approximately 32° (caudal angulation) and 55° (cephalad angulation), differing from the conventional 45°. Measurement reliability was high. Adopting sample-specific angles has the potential to improve image quality; actual clinical effectiveness requires confirmation in prospective studies.