目的:利用自由呼吸动态磁共振成像(D-MRI)定量研究中国肺功能正常人群的膈肌和胸壁运动特征。
方法:74名男性受试者(平均年龄,37±11岁)前瞻性登记,他们接受了高分辨率CT(HRCT),肺功能测试(PFTs),和D-MRI在同一天。在安静和深呼吸期间,通过梯度回波序列获得了D-MRI。分别通过测量胸椎前后径(AP)评估隔膜和胸壁的运动,左右直径(LR),头尾直径(CC),以及吸气末期和呼气末期的胸廓面积比。年龄的影响,体重指数(BMI),并分析了吸烟对呼吸肌功能的影响。
结果:在安静和深呼吸期间,在三个横向平面上,左右AP的平均比率均大于LR。前膈的平均比率(和,安静:1.04±0.03;深:1.15±0.09)比顶点弱(vs.APD,安静:1.08±0.05,p<0.001;深:1.29±0.12,p<0.001)和后膈(vs.POD,安静:1.09±0.04,p&lt;0.001;深:1.30±0.12,p&lt;0.001)在安静和深呼吸中。与不吸烟者相比,吸烟者左AP和胸廓面积比值显著降低(p<0.05)。然而,AP的比率,LR,CC,不同年龄和BMI的各组之间,每个平面上的胸部面积相似。
结论:在安静和深呼吸期间,胸壁运动在前后方向突出。膈尖和后膈的运动比前膈的运动更为突出。吸烟可能会影响呼吸肌的活动。动态MRI可以定量评估呼吸肌的运动。
Objective: We aimed to quantitatively study the characteristic of diaphragm and chest wall motion using free-breathing dynamic magnetic resonance imaging (D-MRI) in Chinese people with normal lung function. Methods: 74 male subjects (mean age, 37 ± 11 years old) were prospectively enrolled, and they underwent high-resolution CT(HRCT), pulmonary functional tests (PFTs), and D-MRI in the same day. D-MRI was acquired with a gradient-echo sequence during the quiet and deep breathing. The motion of the diaphragm and chest wall were respectively assessed by measuring thoracic anteroposterior diameter (AP), left−right diameter (LR), cranial−caudal diameter (CC), and thoracic area ratios between end-inspiration and end-expiration. The effect of age, body mass index (BMI), and smoking on respiratory muscle function was also analyzed. Results: The mean ratio of right and left AP was greater than that of LR on three transversal planes during both quiet and deep breathing. The mean ratio at the anterior diaphragm (AND, Quiet: 1.04 ± 0.03; Deep: 1.15 ± 0.09) was weaker than that of the apex (vs. APD, Quiet: 1.08 ± 0.05, p < 0.001; Deep: 1.29 ± 0.12, p < 0.001) and posterior diaphragm (vs. POD, Quiet: 1.09 ± 0.04, p < 0.001; Deep: 1.30 ± 0.12, p < 0.001) both in quiet and deep breathing. Compared with non-smokers, the left AP and thoracic area ratios in smokers were significantly decreased (p < 0.05). However, the ratios of AP, LR, CC, and thoracic area on each plane were similar among groups in different age and BMI. Conclusions: During both quiet and deep breathing, the chest wall motion is prominent in the anteroposterior direction. The motions of diaphragm apex and posterior diaphragm were more prominent than that of the anterior diaphragm. Smoking may affect the respiratory muscle mobility. Dynamic MRI can quantitatively evaluate the motion of respiratory muscles.