Left lower lobe collapse
This initial CXR, demonstrates a mass with lobulated contour is projected over left hilar shadow. Note that the hilar vessels are visible through the mass. This constitutes the 'hilum overlay sign' and indicates that the mass is not in anatomical contact with the hilum of left lung (although loosely, we still call it a 'left hilar mass' in day to day reporting!)
CXR few weeks later
Progressive left lower lobe collapse as the cancer causes stenosis of LLL bronchus. There are associated signs of volume loss in left lower chest
CXR few weeks later still
Further progressive left lower lobe collapse as the cancer causes stenosis of LLL bronchus. The lobe is completely collapsed and is hard to see, other than as loss of the outline of the descending aorta. There are associated signs of volume loss in left lower chest.
This series of chest films quite nicely demonstrate progressive left lower lobe lung collapse due to bronchostenotic cancer and shows how when collapse is complete, it is secondary signs (volume loss) which provide the clue to the diagnosis.
- http://www.radiologyassistant.nl/en/4620a193b679d http://www.learningradiology.com/radsigns/radsignspages/H-radsigns.htm http://radiographics.rsna.org/content/27/3/657.figures-only