Computer-aided Three-dimensional Reconstruction Research Articles

Postnatal developmental changes in facial nerve morphology. Computer-aided 3-D reconstruction and measurement.

Accurate measurements of the lengths and angles of the facial nerve were obtained in eight normal human temporal bones of varying ages from 7 days to 76 years. Measurements were made on serial histological sections, using computer-aided three-dimensional (3-D) reconstruction. The most noteworthy of the findings demonstrated that both the mastoid portion of the facial nerve and the segment of the facial nerve between the second genu and the divergence of the chorda tympani nerve lengthened with age. The mastoid segment lengthened more significantly than the latter, indicating the facial canal grows more than the facial nerve in its mastoid portion. This difference in growth rates results in the site of the chorda tympani nerve divergence shifting with age relative to the stylomastoid foramen.

Molecular anatomy of the developing heart

Why the embryonic heart can function without one-way valves and without a conduction system, and why the embryonic atrium and ventricle function essentially as they do in the adult, are elementary questions in cardiac embryology. These questions can now be addressed, thanks to the recent development of molecular cell markers, their application by immunohistochemistry and/or in situ hybridization, and the development of advanced computer-aided three-dimensional reconstruction programs.

Postnatal development of the vestibular aqueduct in relation to the internal auditory canal. Computer-aided three-dimensional reconstruction and measurement study.

To investigate a possible developmental relationship between the internal auditory canal (IAC) and the vestibular aqueduct (VA), we made the following measurements in 10 normal temporal bones from individuals 4 months to 70 years of age at death, using a computer-aided three-dimensional reconstruction and measurement method: the volume of the VA, the length of the IAC, and the distance between the IAC and the external aperture of the VA. The degree of periaqueductal pneumatization was also assessed qualitatively by means of a light microscope. The three parameters increased postnatally in parallel with the development of the periaqueductal air cells, and all pairwise comparisons of these parameters showed a statistically significant correlation. Our results indicate that the IAC and VA develop synchronously and in parallel with the development of the periaqueductal air cells. We believe that an understanding of this relationship will be of help during surgery involving the IAC and VA, and may shed some light on the morphological features of Meniere's disease.

The anatomy of the porta hepatis in patients with preduodenal portal vein, with special reference to portoenterostomy for biliary atresia

The aims of this study were to demonstrate the anatomic relationship between portal vein (PV) branches and hepatic ducts in the porta hepatis in individuals with preduodenal portal vein (PDPV) and to examine the validity of portoenterostomy (Kasai procedure) for patients with biliary atresia (BA) and PDPV. The porta hepatis of four subjects with PDPV without BA was dissected. Similar dissection supplemented by computer-aided three-dimensional reconstruction of the hilar structures was undertaken in a patient with BA and PDPV who underwent an unsuccessful Kasai procedure and died at 5 months of age. In three of the four subjects with PDPV alone, PV branches and extrahepatic bile ducts were abnormally arranged in the porta hepatis, some of the hepatic ducts entering the liver substance posterior, and occasionally lateral, to the main PV branches. The three-dimensional study showed that the original right main intrahepatic bile duct was located anterolateral to the portoenterostomy, which had been placed just anterior and to the right of the PV bifurcation. These findings strongly suggest that the PV may not be a reliable landmark for the Kasai procedure in patients with BA and PDPV.

Morphometry and distribution of displaced dopaminergic cells in rat retina

The majority of dopaminergic (DA) cells, labeled by tyrosine hydroxylase (TH) immunohistochemistry, are located in the amacrine cell layer (i.e., the innermost sublayer of the inner nuclear layer) in the rat retina. We describe a small population of DA cells, observed in retinal wholemounts, that are displaced to either the inner plexiform layer (DAIcs) or the ganglion cell layer (DAGcs). Contrary to some other species, such cells are few in number in the rat retina. Their systematic study was made in young and adult retinas by retinal mapping, camera lucida drawing, and computer-aided three-dimensional reconstruction. Located predominantly in the superior temporal quadrant, they are observed as soon as the second postnatal day. Most of the morphometric parameters studied were not significantly different between the two types of displaced DA cells, despite the characteristic appearance of interstitial cells. Two hypotheses are proposed for the origin of their displacement: either it is accidental or programmed. Our results favor the former possibility.

Brain morphogenesis of the red sea bream, Pagrus major (teleostei).

Post-embryonic morphogenesis and regional volumetric growth of the brain in larval and juvenile red sea bream, Pagrus major, were analyzed by employing a computer-aided three-dimensional reconstruction of serial sections of the head. The relative volume of the optic tectum rapidly increases after hatching until day 8, implying the importance of the visual sense for the first feeding, which begins on day 4. The differentiation and outgrowth of the primary gustatory center in the medulla after day 43 may reflect the increasing number of taste buds, suggesting a relationship to the onset of benthic feeding as juveniles. The rather rapid increases in the relative volumes of the corpus and valvula cerebelli after day 28 and their progressive morphogenesis may be correlated with improved motor performance. The relative volumes of the octaval-lateral line centers, including the eminentia granularis and the crista cerebellaris, and the relative volume of the torus longitudinalis, increase in parallel with those of the corpus and valvula cerebelli.

Computer‐aided 3‐D reconstruction and measurement of the facial canal and facial nerve. I. cross‐sectional area and diameter: Preliminary report

Using a computer-aided three-dimensional (3-D) reconstruction method, measurements were made at eight representative sites of diameters and the cross-sectional area of the facial canal, facial nerve, and the space between the canal and nerve. Materials used were serial histology sections of seven normal human temporal bones obtained from individuals of different ages. Two areas of decreased cross-sectional area of the facial canal were found: the proximal part of the labyrinthine portion and the middle part of the tympanic portion. These narrowings in the canal appeared to be correlated with decreased superior-inferior diameter of the facial canal in those portions, especially in adult temporal bones, and also with decreased cross-sectional area, both of the nerve and of the space between the canal and the nerve, in these portions. The developmental etiology of these narrowings is speculated on, and their possible relationship to Bell's palsy is discussed.

Computer-aided three-dimensional reconstruction and tumor volume measurement of malignant melanomas by the aid of 20-MHz-sonography

Computer-aided three-dimensional reconstruction and tumor volume measurement of malignant melanomas by the aid of 20-MHz-sonography

Computer-aided three-dimensional reconstruction and measurement of facial canal dehiscence.

Location, shape and dimensions of the dehiscence in the facial canal to the middle ear space were studied in 20 temporal bones obtained from 19 individuals aged 1 day to 72 years at death by using our computer reconstruction and measurement method. The most frequent site of dehiscence was the oval window area (70%), particularly in its posterior half and on the inferior to inferomedial aspect of the canal. The shape of the dehiscence tended to be oval in the oval window area, but rather irregular in the other areas. The dehiscence ranged from 0.4 to 2.64 mm in length, from 0.12 to 1.59 mm in width, and from 0.03 to 1.87 mm2 in surface area. Proximity of these dehiscences to the field of otological surgery is stressed.

Torsion of the human semicircular canals and its influence on their angular relationships.

We used a computer-aided three-dimensional reconstruction and measurement method to measure torsion of the the semicircular canals (SCCs) in 10 normal human temporal bones from 10 individuals (3 months to 76 years old). Torsion of each SCC was measured as the angle between the "standard line" (the line connecting the ampullated and nonampullated ends of the SCC) and the plane of greatest SCC torsion. Torsion was greatest for the anterior SCC (16.4 +/- 3.6 degrees), followed by the lateral SCC (9.5 +/- 6.7 degrees) and the posterior SCC (8.5 +/- 4.2 degrees). The angles between the overall plane described by each SCC and the other SCCs between the anterior and lateral, the anterior and posterior, and the posterior and lateral SCCs were also measured and were found to be 78.7 +/- 10.0, 107.9 +/- 5.5, and 87.3 +/- 6.9 degrees, respectively. Finally the angles between the torsion plane of each SCC and the others were measured and found to be 92.6 +/- 15.4, 95.8 +/- 11.2, and 90.9 +/- 8.3 degrees, respectively. These results indicate that on average torsion in the SCCs tend to bring the angle between pairs of SCCs close to a right angle. This tendency to have a right angle between SCCs is thought to promote optimal vestibular function. Speculation is offered regarding the etiology of the greater torsion of the anterior SCC.

Three-dimensional surgical anatomy for stapes surgery computer-aided reconstruction and measurement.

To define anatomical relationships relevant to stapes surgery, computer-aided three-dimensional reconstruction and measurement were performed on nine normal temporal bones. The mean distance from the inferior portion of the long process of the incus to the center of the oval window was 3.80 mm. The shortest distance from the center of the oval window to the utricular macula, saccular membrane, and macula averaged 1.37, 1.60, and 2.13 mm. Surgery directed posteromedial-superior from the oval window was found to be most dangerous because it would come so close to the utricular macula; a posteromedial-inferior approach was found to be safest. The distance from the inferior margin of the oval window inferiorly to the cochlear duct in the hook portion ranged between 0.58 and 1.29 mm, suggesting that when a drill hole is made on the inferior margin of the oval window to lift up a depressed stapes footplate, the hole should not be greater than 0.5 mm in diameter.

The mucus-hypersecreting tumor of the pancreas. Development and extension visualized by three-dimensional computerized mapping.

Mucus-hypersecreting tumor of the pancreas appears as dilated ducts and cystic spaces filled with mucus. To determine where such tumors arise and how they extend, computer-aided three-dimensional reconstruction was done of the ductal system. This also was used to visualize the spatial relationships among epithelial hyperplasia, dysplasia, and carcinoma in situ (CIS). Surgically removed pancreases were studied from 12 patients with mucus-hypersecreting tumors. The specimens were fixed in buffered formaldehyde solution 10%, embedded in paraffin and semiserially sectioned at 3 microns at an interval of 60 microns. The ductal contours were differentiated among ducts lined by ordinary epithelia, hyperplastic epithelia, dysplastic cells, or CIS and were inputted into a computer system that integrated a three-dimensional image of ducts in the display. (1) The tumors arose in the main pancreatic duct or its subbranches, and the cysts corresponded to segments expanded by the superficial growth of tumor cells; (2) areas of CIS arose in zones of preceding dysplasia, suggesting a dysplasia-carcinoma sequence; and (3) dysplastic or cancerous cells often extended intraductally over the dilated segments of ducts.

Computer-aided three-dimensional measurement of the human vestibular apparatus.

Using a computer-aided three-dimensional reconstruction and measurement method, 12 measurements were made to determine the dimensions of the maculae, cristae ampullares, and semicircular canals in 18 temporal bones from nine pairs of age-matched male and female individuals (1 day to 76 years old). The surface areas of the utricular and saccular maculae were significantly larger in male than in female specimens (two-way analysis of variance, F = 9.00, df = 1, p less than 0.01; F = 4.57, df = 1, p less than 0.05, respectively). The width of the utricular macula and the length of the saccular macula were also significantly greater in male than in female specimens (two-way analysis of variance, F = 5.17, df = 1, p less than 0.05; F = 4.33, df = 1, p less than 0.05, respectively). Finally, the three semicircular canals were larger in diameter in male vs. female specimens; this difference was statistically significant for the superior semicircular canal (two-way analysis of variance, F = 10.74, df = 1, p less than 0.01). By contrast, none of these dimensions of those vestibular structures showed any significant change in size with advancing postnatal age. We propose from these findings that there appears to be sexual dimorphism in the vestibular apparatus.

Three-dimensional anatomy of human Scarpa's ganglion.

Using a computer-aided three-dimensional reconstruction and measurement method, the authors studied the shape and dimensions of Scarpa's ganglion and interrelations of the ganglion to nearby important anatomical structures in 10 normal human temporal bones obtained from 10 individuals of different ages (12 gestational weeks to 72 years). In the postnatal cases, Scarpa's ganglion was shaped like a distorted hourglass. Although the shape of the ganglion varied somewhat among specimens, a superior division, inferior division, and isthmus ganglionaris were distinguishable in each case. Volume of the ganglion was relatively consistent after birth, so that width and height of the ganglion were inversely correlated with each other (linear regression analysis, P less than .05). There seemed to be, however, a possible postnatal increase in the distances from the ganglion to neighboring structures and in the length of the internal auditory canal; these increases were probably the result of postnatal growth of the temporal bone. Moreover, the width of the ganglion in any single specimen was found to correlate significantly positively with the distances from the ganglion to the vestibular end-organs and the length of the internal auditory canal in that specimen (linear regression analysis, P less than .01). This finding suggests that Scarpa's ganglion may be elongated secondary to the elongation of the vestibular nerve due to the growth of the temporal bone. In fetuses, each portion of the ganglion was less clearly identifiable than that portion in postnatal cases. The dimensions of Scarpa's ganglion were found to have reached maturity around the time of birth.

Ultrastructural organization of Rhizophlyctis harderi zoospores and redefinition of the type 1 microbody – lipid globule complex

Because ultrastructural features of zoospores are considered primary characters in Chytridiomycete systematics, computer-aided three-dimensional reconstructions of serial sections were used to analyze zoospore fine structure of Rhizophlyctis harderi, a questionable member of the genus Rhizophlyctis. A secondary centriole was parallel to the kinetosome, but the nucleus was not structurally or spatially associated with the kinetosomes. Mitochondria and cisternae associated with vesicles bounded a ribosomal aggregation in which the nucleus was partially embedded. The peripheral cytoplasm between the plasma membrane and ribosomal aggregation contained α-glycogen particles, vacuoles with osmiophilic globules, vesicles with clear matrices, and vesicles with electron-dense cores. A new, compound form of microbody – lipid globule complex (MLC) was identified. This type of MLC incorporated posteriorly located lipid globules associated with rumposomes and anteriorly located lipid globules associated with simple cisternae, microbodies, and highly branched mitochondria. Based on these and other recent observations, the concept of the type 1 MLC was redefined. Sources for variation in ultrastructural features of zoospores are discussed. Zoospore ultrastructure of R. harderi is different from that described for other chytrid zoospores. Key words: Chytridiomycetes, microbody – lipid globule complex, Rhizophlyctis, taxonomy, ultrastructure, zoospore.

Three-dimensional computer-aided reconstruction and measurement of the temporal bone for singular neurectomy.

A computer reconstruction method was used to study five normal temporal bones for the three-dimensional anatomy necessary for singular neurectomy. The length of the singular canal was 4.9 +/- 0.6 mm. The distal portion of the singular canal courses at a sharp angle (48.2 degrees) to the direction of the transmeatal surgical approach for this operation. The reconstructions indicated that the singular canal can be exposed by introducing a drill through the external auditory meatus at a point 0.71 mm posteroinferior to the posteromedial margin of the round window on the saucerized medial wall of the round window niche. The distance from this site to the distal end-portion of the singular canal averaged 1.47 mm. The point on the drilling course (from the drilling site to the singular canal) closest to the vestibular end of the hook portion of the cochlea was 0.48-1.00 mm from the drilling site. The reconstructions also indicated that the dissection should proceed superomedially, if necessary, after a 1-mm-deep straight dissection along the transmeatal approach. The ampulla of the posterior semicircular canal, cochlear aqueduct and inferior cochlear vein were all found to lie within 2 mm of the drilling point.

Periductal vessels of the endolymphatic duct.

Light microscope was used to examine the rich vascular plexus surrounding the human endolymphatic duct, both in the periductal loose connective tissue and in the bony channels surrounding the bony vestibular aqueduct. We also performed computer-aided three-dimensional reconstruction on one serially sectioned region of the endolymphatic duct. We found an anastomotic and looping network of vessels residing in the loose connective tissue close to the epithelium of the endolymphatic duct. This network often received a vascular contribution from the vessels in the periaqueductal bony channels. These findings were verified by light microscopic examination of 50 temporal bone specimens. Concurrent with this finding, histologic examination also showed different characteristic features of the vascular system of the endolymphatic duct-proximal sac areas and of the more distal parts of the endolymphatic sac. These features include the arrangement, quantity, and contents of the periaqueductal bony channels, as well as the organization of the bone containing these periductal bony channels. Findings from this study help the understanding of the anatomy of the human endolymphatic duct. In addition, they support and supplement earlier observations of the structure of the endolymphatic duct. We suggest the possible existence of a periductal vasculature system, similar in pattern to that in the endolymphatic sac, but specialized to work with the duct to aid its function.

Three-dimensional Representation and Quantification of Endosomes in the Rat Kidney Proximal Tubule Cell

The organization of the endosomal compartment in the rat kidney proximal tubule cell was studied by computer-aided three-dimensional reconstruction based on tracing of serial thin sections. Besides the well-documented endocytic elements such as small vesicles, tubules and large vacuoles, the endosomal compartment contained a prominent structural complex consisting of a central vacuolar element (with diameters up to 2000 nm) and associated systems of radiating tubular profiles. The large endosomes examined had from two to twenty-four tubules as straight or bending extensions directed randomly from the central vacuole. The tubules were 70-90 nm in diameter and varied with the length up to 1500 nm. Quantitative evaluation from examples of the large endosomes with more than ten tubular extensions, showed that 25-40% of the membrane resided in the tubular portion in contrast to 5-10% of the volume. These results indicate the high efficiency of the role of the endosomal tubules as a mediator of the membrane recycling, because the tubules simultaneously allow retention of most of the content in the central vacuole during the recycling process.

Fine structural characteristics of testicular cord formation in the developing rabbit gonad

This paper presents morphological (light- and electron-microscopical) evidence for the role of the mesonephros in contributing cells to the differentiating indifferent gonad and, after sexual differentiation, to the testis. A continuous process is revealed during which segregation of cells occurs from the developing and regressing mesonephros. Additionally, the complementary role of the coelomic epithelium in gonadal ridge and testis formation is demonstrated. The differentiation of testicular cords, their remodelling from a primary reticulum, and the composition and further change of the cellular content during the period after sexual differentiation is described using a computer-aided three-dimensional reconstruction system. Apart from these morphogenetic events, cytodifferentiation in the somatic cells of the indifferent gonad and of the early differentiated testis is demonstrated using indirect immunofluorescence in combination with monoclonal antibodies to the intermediate filament proteins keratin 8 and 18 and vimentin. The immunohistochemical results show that different forms of cytodifferentiation coexist among the somatic cells present in the indifferent gonad and in the testis early after sexual differentiation.

Three-dimensional Reconstruction of Goblet Cells in the Rabbit Conjunctivum

Goblet cells in the rabbit bulbar conjunctivum were not real "goblet," but were variable in shape. The diversity of the morphology became evident by means of computer-aided three-dimensional reconstruction. All of the cells reconstructed (N = 5) were in touch with the basal lamina, and were open to the epithelial surface. Their cytoplasm was filled with secretory granules (about 71% of the cellular volume, in average), while the nucleus occupied only 5.3%.