Image analysis of hemosiderin-laden macrophages in bronchoalveolar lavage fluid.

The aim of this study was to assess quantitatively the relationship between the number of iron-laden macrophages, extent of hemosiderin content and amount of dark-stained hemosiderin clumps in bronchoalveolar lavage (BAL) fluids. The series included specimens from 20 subjects whose BAL had yielded iron-laden macrophages. Six had developed hemoptysis 3-15 days prior to BAL. Quantitative studies were performed on smears stained by the ferrocyanide reaction, using true color image analysis for image segmentation. A top-hat function based on mathematical morphologic concepts was used for extraction of dark clumps of hemosiderin. The results demonstrated the presence of iron-laden macrophages three days after hemoptysis. There was a moderate correlation between the percentage of macrophages and amount of hemosiderin content, but the extent of dark-stained clumps did not increase in parallel to the increase in hemosiderin content and probably represented an advanced stage in the phagocytic processing of hemosiderin formed from engulfed red blood cells. The main difference between subjects with and without previous hemoptysis was higher values for dark clumps of hemosiderin in the former.