Couldn I just use a cell sorter followed by microscopy to do what the ImageStreamX does?
It is easy to conceive of using a cell sorter to isolate rare cells on a slide for subsequent imaging. In practice, this is very difficult to accomplish because the cells of interest must be phenotypically distinct from other cells in the sample in order to be sorted with high purity. In most cases, a mixture of cells is sorted which cannot be differentiated by the microscope due to its limited sensitivity and fewer fluorescent colors relative to the sorter. Even if a pure population is sorted, the microscope is limited in its ability to quantitate multicolor imagery accurately due to fluorescence crosstalk. Even if this limitation is overcome by using a limited number of spectrally distinct colors, the microscope is constrained in the number of cells it can image in a reasonable period of time, so statistical population information will be unavailable. Variation from cell to cell in small analysis populations can mask subtle differences that the analysis of a larger population would r