Classification of secondary pulmonary lobular structural imaging signs
To define the imaging features of secondary pulmonary lobular structure on CT images, then building simulation schematics to strengthen cognition and serve as a unified standard for evaluation (Fig.1, 2). The secondary pulmonary lobular structural imaging signs are defined as a set of CT imaging of pulmonary lobules and its related structures, which are typified by five major categories: Ⅰ Lobular size sign, Ⅱ Fusion lobular sign, Ⅲ interlobular septal thickening sign, Ⅳ intralobular interstitial thickening sign, Ⅴ intralobular vascular thickening sign (Fig. 2).