A computer-aided three-dimensional reconstruction of brain structures using high level computer graphics

A practical three-dimensional reconstruction method to measure the volume of the sexually-dimorphic central nucleus of the medial preoptic area (MPOC) of the rat hypothalamus

Published estimates of the volume of the sexually-dimorphic central nucleus of the medial preoptic area (MPOC) have been quite variable both within and between laboratories. To obtain MPOC volume, most experimenters began with a two-dimensional (2-D) approach. They outlined the MPOC on each of several individual sections; then they added up the area contained on each section and multiplied the total by the section thickness. A 3-D reconstruction approach, although promising, has been somewhat impractical until recently due to the requirements for highly specialized software and massive computing support. Here, we describe the application of commercially-available PC-based software to measure MPOC volume by 3-D reconstruction. Male and female Sprague-Dawley rats, 24 or 50 days of age, were perfusion-fixed with 10% neutral phosphate-buffered formaldehyde. Following processing and embedding, a series of 20-microm sagittal paraffin sections were cut and mounted onto slides. After staining with cresyl violet, they were digitized using a microscope-mounted video camera connected to a frame-grabber in a Pentium-class computer (MCID-M5+). In addition to the MPOC, the anterior commissure, fornix, paraventricular nucleus, medial division of the bed nucleus of the stria terminalis, third ventricle and the bed nucleus of the anterior commissure were identified on the screen image and outlined using a computer mouse. These outlines were then aligned and rendered in 3-D with a solid overlay. The additional areas, such as anterior commissure, form landmarks within 3-D space to improve the accuracy with which the MPOC may be located and outlined. The reconstruction provides a striking illustration of the geometric relations between the structures of the anterior hypothalamus in the male and female rat. Moreover, the volumes determined from the overlays were reproducible between repeated studies in our laboratory. Our volume measurements confirm the sexual dimorphism previously reported for MPOC volumes, and provide a relatively quick, accurate and reliable protocol that should be useful in future experimental studies of environmental estrogenic compounds.

[Stereotactic localization in medical imaging. Technical and methodologic aspects]

Stereotactic neurosurgery and stereotactic radiation therapy require the three-dimensional localization of lesions for biopsy or for treatment planning. The aim of this paper is the description of methods used in the different imaging modalities: x-ray teleradiography, digital subtracted angiography, computed tomography, and nuclear magnetic resonance imaging. The simple pin-target locating techniques are distinguished from those serving to the definition of volumes target necessary to treatment planning. Performances and difficulties of these techniques are emphasized. The specific methodology developed in Lille is described as an example. Organizational aspects and necessary quality controls for a good progress of the entire procedure, from imaging to treatment, are also discussed.

Fiducial points for three-dimensional computer-assisted reconstruction of serial light microscopic sections of umbilical cord

Fascicles of human sural (peripheral sensory) nerve were used as external fiducial points (FP) for accurate registration of serial light microscopic sections in three-dimensional reconstruction of human umbilical cord. This paper describes a method for embedding the FPs within the paraffin wax block simultaneously with the specimen to be sectioned. Using a new design of embedding box, the FPs are embedded close to the specimen and are transferred to the slides as part of the tissue sections. Three to four FPs were used to align and scale the serial tissue sections for digitization and computerized reconstruction, using a commercially available software program on IBM-compatible 80386 hardware. A three-dimensional solid surface graphic model of a segment of human umbilical cord was generated.