A detailed analysis of the edge of a lamellipodium of an unlabeled endothelial cell. This example illustrates analysis by counts per pixel and HSI. (a-c) Three MIMS images acquired in parallel at (a) 12C14N-, (b) 12C-, and (c) 16O-. Field: 60 × 60 μm (256 × 256 pixels); acquisition time 2 min. (d) HSI image of the ratio 12C14N-/12C- (the numerator has been multiplied by 10). Magenta dots (arrowed) indicating areas of high relative 15N incorporation appear at the edge of the lamellipodium. Field: 60 × 60 μm (256 × 256 pixels). (e) HSI images of the ratios 12C14N-/12C- (left) and 16O/12C14N- (right; the numerator has been multiplied by 10). The regularly spaced dots (arrowed) can be seen at the edge of the lamellipodium. (f) At each pixel, arranged from top to bottom, are the values of the 12C14N- counts, the 12C- counts and the 12C14N-/12C- ratio (multiplied by 10) for the pixels shown in the inset in (e). (g) The corresponding values at each pixel, arranged from top to bottom, for the 12C14N-/12C- ratio values (multiplied by 10) and the 16O-/12C14N- ratio (multiplied by 10). (h,i) Bar graph of the mean count values of 12C-, 12C14N- and 16O- on (h) the dot at the periphery of the lamellipodia and (i) the edge of the lamellipodia.