3-DIMENSIONAL RECONSTRUCTION OF HISTOLOGI CAL SERIAL SECTIONS ON THE COMPUTER

This paper reports the development of an objective and time-saving met hod for the three-dimensional reconstruction of sectioned morphologica l specimens on the computer. The development of a fiducial marker tech nique, the design of program extensions for the automatic thresholding and realignment of images, and a technique for the transfer of marker -derived reference points into images of higher magnification are desc ribed. The method is based on the use of resin as embedding material a nd drill holes as fiducials. Images are digitized by a video camera, a nd NIH-Image is used for image processing. Special macros were written for the automation of a number of operations, such as object and mark er segmentation, image reorientation, image scaling, dirt removal, and marker transfer. The so-treated image series were transferred to a wo rkstation and were reconstructed using ''Image Volumes''. The reconstr ucts obtained from this largely automated technique exhibit a perfect alignment of the sections. The 3-D representations of the sectioned ob jects have a much higher degree of objectivity than those obtained by manual image orientation or by semiautomated techniques that do not us e fiducials.