INTERLOBULAR SEPTAL THICKENING - PATTERNS AT HIGH-RESOLUTION COMPUTED-TOMOGRAPHY

Thickening of the interlobular septa is a common and easily recognizab le finding at high-resolution computed tomography (HRCT; 1-2 mm collim ation high-spatial-frequency reconstruction algorithm). Interlobular s eptal thickening at HRCT can be smooth, nodular, or irregular in conto ur. It may be due to fluid, cellular infiltration, or fibrosis. Appare nt thickening of septa at HRCT may also be due to abnormalities in the periphery of the secondary pulmonary lobule adjacent to but not invol ving the interlobular septa. This article illustrates the patterns of interlobular septal thickening at HRCT in various disease entities.