Interlobular septal thickening 2016-07-02T07:21:51Z Interlobular septal thickening on pulmonary HRCT Interlobular lines (pulmonary CT finding) Peripheral lines (pulmonary CT finding) Interlobular septa are 10-20nm long structures at the border of the secondary pulmonary lobules and which are usually perpendicular to the pleura in the periphery of the lung. Interlobular septa are composed of connective tissue and contain pulmonary venules and lymphatics. Diseases that affect one of the components of the interlobular septa may lead to thickening of the septa, which makes the visible on computed tomography (CT) scans. Some of the diseases that may be associated with this phenotypic feature are pulmonary edema, pulmonary lymphangitis carcinomatosis, leukemic or lymphomic involvement of the lung, diffuse alveolar hemorrhage, Nieman-Pick disease, and pneumonia. Presence of thickening of the interlobular septa of the lungs as seen on a CT scan. Septal lines (pulmonary CT finding) Short lines (pumonary CT finding) Septal thickening (pulmonary CT finding) Pulmonary interstitial thickening