Three-dimensional electron microscopy of entire cells

The digital processing of serial electron-microscope sections containing laser-induced topographical references allows a three-dimensional (3-D) reconstruction of entire cells at a depth resolution of 40-60 nm by the use of novel image analysis methods. The images are directly processed by a video-camera placed under the electron microscope in TEM mode or by the electron counting device in STEM mode. The deformations associated with the cutting of embedded cells are back-calculated by new computer algorithms developed for image analysis and treatment. They correct the artefacts caused by serial sectioning and automatically reconstruct the third dimension of the cells. Used in such a way, our data provide definitive information on the 3-D architecture of cells. This computer-assisted 3-D analysis represents a new tool for the documentation and analysis of cell ultrastructure and for morphometric studies. Furthermore, it is now possible for the observer to view the contents of the reconstructed tissue volume in a variety of different ways using computer-aided display techniques.