SIÊU ÂM ĐOẠN TẬN ỐNG NGỰC Ở NGƯỜI BÌNH THƯỜNG: ĐẶC ĐIỂM HÌNH ẢNH VÀ THAY ĐỔI ĐƯỜNG KÍNH THEO CHU KỲ HÔ HẤP

Abstract

Objectives: To describe the ultrasound characteristics of the terminal thoracic duct (TTD) in healthy adults and assess changes in its diameter during different respiratory phases. Methods: A cross-sectional descriptive study was conducted on 52 healthy volunteers examined at Hanoi Medical University Hospital. All participants underwent an ultrasound of the TTD during three respiratory phases: Normal breathing, maximal inspiration, and maximal expiration. Standard imaging planes included the clavicle-parallel plane, the left internal jugular vein-parallel plane, and the clavicle-perpendicular plane. The TTD diameter was measured on a longitudinal view at 1cm proximal to the venous angle, using inner-to-inner wall measurements. Results: The study included 52 subjects (17 males, 35 females) with a mean age of 36.8 ± 12.4 years. The most common drainage site of the TTD was the left internal jugular-subclavian venous confluence (50%), while direct drainage into the left subclavian vein accounted for 19.2%. A single common trunk was observed in 94.2%, and anatomical variants in 5.8%. No significant association was found between age and TTD diameter (p = 0.64). The mean TTD diameter was 1.7 ± 0.50 mm; it increased during maximal inspiration and decreased during maximal expiration (p < 0.05). Conclusion: Ultrasound provides reliable visualization of the TTD in healthy individuals. TTD diameter varies with respiration, reflecting the impact of intrathoracic pressure on lymphatic flow.