An on-line chromatic and scale-space microvasculature-tracing analysis for transmitted light optical images

Limited contrast in optical images from intravital microscopy is problematic for analysing tumour vascular morphology. Moreover, in some cases, changes in vasculature are visible to a human observer but are not easy to quantify. In this paper two quantitative on-line algorithms are presented: scale-space vessel tracing and chromatic decomposition for tumour vasculature from in-vivo transmitted light optical images. The algorithms were tested on intravital window chamber images of the vasculature from SW1222 human colorectal carcinomas, which were treated with a vascular disrupting agent combretastatin-A-4-phosphate (CA-4-P) or saline. The results confirmed the wellknown effects of CA-4-P on the constriction of vessels. Furthermore, changes in the chromaticity suggest a deoxygenation of the blood with a recovery to initial levels in CA4-P-treated tumours relative to the controls. The algorithms can be freely applied to any vascular image through the CAIMAN (CAncer IMage ANalysis: http://www.caiman.org.uk).