WF Interlobular Septal Thickening CHF Kerley B Lines and Thickening of the Interlobular septa74-year-old female presents in CHF and an echo showing reduced EF (35%)CT scan from a coronary CTA with a limited field of view above, and magnified below shows thickening of the interlobular septa extending to the periphery and in contact with the pleural surface indicating moderate CHFAshley Davidoff MD TheCommonVein.net 003H RnD There are other causes of interlobular septal thickening, caused by involvement of the venule, the lymphatics or the septal connective tissue