- 期刊
縱膈腔在站立與仰臥胸部X光之變化評估
Comparison of Mediastinum between Upright and Supine Chest X-ray
摘要
在胸部X 光片中，肺部兩側所包圍的部分皆屬於縱膈腔，縱膈腔主要是醫生用來診斷心臟疾病或左、右邊心室肥大、胸腔內甲狀腺腫大、縱膈腔淋巴結腫大、主動脈擴張、食道擴張或是縱膈腔腫瘤的重要指標之一。但是要注意的是縱膈腔在仰臥姿勢會因X 光投射方向與心臟解剖位置之相關性及重力影響及X 光管球與病人距離不同而造成影像與站立姿勢時稍有不同，所以本次研究目的在探討站立與仰臥胸部X 光之縱膈腔的差異，以做為醫師在判讀胸部X 光時的參考。本研究主要收集本院在三日內有接受站立及仰臥之胸部X 光患者共60 位，然後利用影像工作站之測量軟體，測量胸部X 光影像上縱膈腔各部位的寬度，算出心胸比、中膈胸比、動脈弓中膈比三者來表示縱膈腔比例大小，然後利用統計軟體來計算評估站立及仰臥之胸部X 光縱膈腔之變化。根據統計心胸比部分仰臥姿勢比站立姿勢放大率平均值約在1.12、在中膈胸比部分放大率平均值約在1.21、在動脈弓中膈比部分放大率平均值約在0.95。其它縱膈腔各部位的寬度在本研究也顯示仰臥的胸部X 光縱膈腔的寬度比站立姿勢來的大。所以醫師在判讀胸部X 光時必須考慮到病人的攝影姿勢是站立或是仰臥照相，放射師則在檢查前須依醫師醫矚作為擺位參考。
並列摘要
In Chest X-ray film, mediastinum is enclosed by two sides of the lung. Mediastinum is used by doctor to diagnose heart disease or left/right ventricular hypertrophy, thyromegaly in chest, lymphadenectasis in mediastinum, aortectasia, esophagectasia; or it is one of the important indications of neoplasm in mediastinum. However it should be noted that mediastinum image in supine position is slightly different from that in upright position due to the different anatomical positions influenced by gravity; the direction of X-ray beam, and the differences of distance between X-ray tube and patient as well. Therefore, the aim of this research is discussed the variances of mediastinum in upright and supine position, as reference for doctors in reading Chest image. This study recruited 60 subjects who underwent Chest X-ray examination in supine and upright position within 3 days. Estimated lengths of various parts of mediastinum in workstation measuring software to work out cardiothoracic ratio, MTR, AMR were used to show the size of mediastinum. Afterwards, biostatistics was performed to evaluate the changes of mediastinum in upright and supine posture on Chest X-ray. According to the result, comparing cardiothoracic ratio in supine and upright posture, the average value of magnification ratio was about 1.12, while for MTR, average value of magnification ratio was about 1.21, for aorta arch/mediastinum ratio (AMR), average value of magnification ratio was about 0.95. And other data revealed that the length of the mediastinum in supine position is magnified in Chest image. Thus, when doctors read Chest image, the patients’ postures undergoing X-ray examination should be considered. In addition, the technologist should administer examination according to doctor’s order as reference of position.