二次小葉：２００４ Fleischner Lecture

Thin-Section CT of the Secondary Pulmonary Lobule: Anatomy and the Image—The 2004 Fleischner Lecture
Published online before print March 16, 2006, doi: 10.1148/radiol.2392041968 May 2006 Radiology, 239, 322-338.

Diagram shows anatomy and dimensions of secondary lobule and pulmonary acinus. Two secondary pulmonary lobules in the lung periphery are illustrated, with approximate dimensions of their components indicated.

alveolengange



Georg Rindfleisch (in 1875) は、”acinus”という用語を用い、小葉下肺構造ユニットをしめした。
次々とより小細気管支に分岐し、細気管支分岐となり、ついには arborizing alveolengange (alveolar passages)まで到達する。
"acinus"は、Rindfleishによれば、二次小葉より構成ユニットの多いもので、小葉のサイズにばらつきが大きい。一方、小葉の辺縁の結合組織中隔により疾患プロセスの影響を受けるため、acinus より、二次小葉の方が重要であるとした。

Secondary pulmonary lobule and acinus as shown by Georg Rindfleisch. The lobular bronchiole is shown dividing into smaller branches, which supply the acini.

“Miller's lobule” and “Reid's lobule.”

“Miller's lobule”

Secondary pulmonary lobule, as shown by Miller. Diagram shows secondary pulmonary lobule from lung periphery surrounded by connective-tissue septa and pulmonary vein branches. Also shown is airway anatomy from the level of the lobular bronchiole to lung periphery. Large circle shows approximate size of an acinus. Smaller circle shows approximate size of a primary pulmonary lobule as defined by Miller. Pulmonary artery branches are shown as thick black structures. (Reprinted, with permission, from reference 21.)

“Reid's lobule”

In 1958, Reid suggested an alternate definition of the secondary pulmonary lobule based on the branching pattern of peripheral bronchioles identified bronchographically rather than on the presence and location of connective tissue septa

Perilobular Pattern: Interlobular Septal Thickening and Peripheral Lobular Abnormalities

・smooth septal thickening


・nodular septal thickening




Centrilobular Abnormalities
・centrilobular nodules


・tree-in-bud sign


・prominent (increased thickness of) centrilobular structures


・centrilobular low attenuation


・Panlobular Abnormalities


・lobular consolidation


・lobular ground-glass opacity



・lobular low attenuation due to mosaic perfusion


・mixed disease and the headcheese sign


・lobular low attenuation due to emphysema