Napadow V J, Mai V, Bankier A, Gilbert R J, Edelman R, Chen Q
Department of of Mechanical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02138, USA.
J Magn Reson Imaging. 2001 Mar;13(3):467-74. doi: 10.1002/jmri.1068.
In clinical practice, the assessment of lung mechanics is limited to a global physiological evaluation, which measures, in the aggregate, the contributions of the pulmonary parenchyma, pleura, and chest wall. In this study, we used an MR imaging methodology which applies two-dimensional bands of inverted magnetization directly onto the pulmonary parenchyma, thus allowing for the quantification of local pulmonary tissue deformation, or strain, throughout inhalation. Our results showed that the magnitude of strain was maximal at the base and apex of the lung, but was curtailed at the hilum, the anatomical site of the poorly mobile bronchial and vascular insertions. In-plane shear strain mapping showed mostly positive shear strain, predominant at the apex throughout inhalation, and increasing with expanding lung volume. Anisotropy mapping showed that superior-inferior axial strain was greater than medial-lateral axial strain at the apex and base, while the opposite was true for the middle lung field. This study demonstrates that localized pulmonary deformation can be measured in vivo with tagging MRI, and quantified by applying finite strain definitions from continuum mechanics.
在临床实践中，肺力学评估仅限于整体生理评估，该评估总体上测量肺实质、胸膜和胸壁的作用。在本研究中，我们使用了一种磁共振成像方法，该方法将二维反转磁化带直接应用于肺实质，从而能够在整个吸气过程中对局部肺组织变形或应变进行量化。我们的结果表明，应变幅度在肺底部和顶部最大，但在肺门处减小，肺门是支气管和血管插入活动较差的解剖部位。平面内剪切应变映射显示大部分为正剪切应变，在整个吸气过程中在肺尖处占主导地位，并随着肺容积扩大而增加。各向异性映射显示，在肺尖和底部，上下轴向应变大于内外轴向应变，而在肺中叶则相反。本研究表明，通过标记磁共振成像可以在体内测量局部肺变形，并通过应用连续介质力学中的有限应变定义进行量化。
