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At least 1,135 records · Page 63Linked to original sources
PubMed2002

Orthognathic surgery outcome analysis: 3-dimensional landmark geometric morphometrics.

Traditional cephalometric analysis of 2-dimensional (2D) landmarks has been limited to distances, indices, and angles. Quantitative results vary depending on what baseline is chosen. Geometric morphometric techniques, such as Procrustes superimposition, assume all landmarks carry equivalent information. Using these methods, landmark coordinates (x, y, z) facilitate comparison of patients and "normative"shapes and assessment of pre- to postoperative outcomes. Pre- and postoperative lateral and frontal cephalograms and stereophotograms were taken of a 48-year-old Caucasian man and a 38-year-old Caucasian woman. Coordinates of 3D hard tissue landmarks were collected directly from scanned cephalograms, and 3D soft tissue landmarks were collected onscreen. Procrustes superimpositions of pre- and postoperative 3D craniodental landmark coordinates and 3D soft tissue coordinates were made, and scatter plots were created to show the surgical shape change separately for each patient. Procrustes superimposition of the preoperative and "normative craniodental data (18-year-old male and female Bolton standards) provided both qualitative and quantitative evaluations of the patients, allowing a better determination of the required treatment. Unlike traditional baseline-dependent methods, Procrustes shape analysis produces a single useful measure of surgical shape change or comparison to normative shape.

Adult↗
PubMed2002

Proportional (fractional) displacement of the Hirschberg corneal light reflection (test): a new easily memorized aid for strabometry; photogrammetric standardization (calibration).

PURPOSE: To improve the usefulness of the Hirschberg Corneal Light Reflection Test (CLRT), using a photogrammetric technique independent of the size of the pupil, and to devise an easily remembered sequence of numbers corresponding to the fractional displacement of the reflection in various approximate angles of esotropia. METHOD: Photographs (slides) were taken of the right eye of 25 young adults using a centered strobe light source to produce the corneal light reflection in 5 prism diopters (PD) increments of adduction from 0 to 90 PD to standardize the Hirschberg CLRT for esodeviations. On a large, dual-projection screen, the eye of the subject looking straight ahead (primary position) was projected on one side and the various slides of the same eye of that subject looking into various degrees of adduction were projected on the other side of the screen. Measurements of the distance between the lateral limbus and the corneal reflection were made with a centimeter rule on the screen. The displacement (shift) of the corneal light reflection was expressed as a fraction of the distance between the lateral limbus and the position of the reflection (in relation to the lateral margins of the pupil) with the eye fixing in the primary position. RESULTS: The values found were 1/4 = 30 +/- 3 PD; 1/3 = 41 +/- 4 PD; 1/2 = 59 +/- 4 PD; 2/3 = 75 +/- 6 PD; and 3/4 = 80 +/- 6 PD. CONCLUSIONS: An easily memorized similar series of values is 30, 40 60, 75 and 80 PD corresponding to 1/4, 1/3, 1/2, 2/3 and 3/4 PD. This is useful to know which prism to pick up to begin the prism alternate cover test efficiently in a small child.

Blinking↗
PubMed2002

Effects of trunk position on back surface-contour measured by raster stereophotography.

A study of the contour of the surface of the back was conducted using the Quantec spinal image system (QSIS; raster stereophotography) and the Vicon 3-dimensional (3-D) motion analysis system with a plaster model of the scoliotic spine. With postural changes in 3 dimensions came alterations in the surface shape of the back. Most changes in QSIS parameters occurred in the coronal plane. The study showed that model 1, with 9 degrees of Q angle (similar to Cobb angle in the coronal plane) in right thoracolumbar scoliosis, altered 3-D metrics less than model 2 did, with 54 degrees of Q angle in scoliosis. The change in the position of the trunk in the transverse plane had a more significant impact on the QSIS parameters. Raster stereophotography has been used clinically to monitor curve progression. Changes in transverse rotation of the trunk correlate significantly with variations in Q angle and axial rotation. Clinicians using a raster stereophotograph system to assess scoliotic deformity need to control postural sway, as doing so results in more stable and reproducible measurements that can be used for clinical follow-up.

Back↗
PubMed1998

[Facial soft tissue features analysis of normal Han race adults in Guangdong Province using computer-assisted-photogrammetric-system].

Facial soft tissue profile features of 150 normal native adults of Guangdong Province were analysed using computer-assisted-photogrammetric-system, which contained parameters written by polar coordinate. The results indicated that normal native adults of Guangdong Han race showed sex and region difference in features of facial profile soft tissue, and those parameters written by polar coordinate were helpful in the further study and clinical therapy.

Adult↗
PubMed2002

Stereological analysis reveals striking differences in the structural plasticity of two readily identifiable glomeruli in the antennal lobes of the adult worker honeybee.

The primary antennal sensory centers (antennal lobes) in the brain of the honeybee are highly compartmentalized into discrete spheres of synaptic neuropil called glomeruli, many of which can be identified according to their predictable size and location. Glomeruli undergo significant changes in volume during the lifetime of the adult worker bee, at least some of which are activity dependent. This study tests the commonly expressed assumption that increases in neuropil volume are accompanied by an underlying increase in the number of synapses present in the tissue. A combination of light and electron microscopy was used to determine total synapse number within two glomeruli, T1-44 and T4-2(1). The Cavalieri direct estimator of volume was applied to 1.5 microm sections of resin-embedded brains. Selected sections were then re-embedded and prepared for transmission electron microscopy. Synapse densities were determined using the physical disector method on electron micrographs. Synapse density and glomerulus volume were combined to give an unbiased estimate of the total number of synapses. In glomerulus T1-44, a significant increase in volume was accompanied by a significant increase in the total number of synapses. In contrast, synapse counts in T4-2(1) remained unchanged, despite a significant increase in the volume of this glomerulus. These results demonstrate that synapse proliferation in antennal lobes of the adult worker bee is highly site specific. Although volumetric changes and changes in synapse number both contribute to the structural plasticity of the antennal lobes, these two components of plasticity appear to be independent processes.

Aging↗
PubMed2002

A comparison of computer-assisted and manual wound size measurement.

Accurate and precise wound measurements are a critical component of every wound assessment. To examine the reliability and validity of a new computerized technique for measuring human and animal wounds, chronic human wounds (N = 45) and surgical animal wounds (N = 38) were assessed using manual and computerized techniques. Using intraclass correlation coefficients, intrarater and interrater reliability of surface area measurements obtained using the computerized technique were compared to those obtained using acetate tracings and planimetry. A single measurement of surface area using either technique produced excellent intrarater and interrater reliability for both human and animal wounds, but the computerized technique was more precise than the manual technique for measuring the surface area of animal wounds. For both types of wounds and measurement techniques, intrarater and interrater reliability improved when the average of three repeated measurements was obtained. The precision of each technique with human wounds and the precision of the manual technique with animal wounds also improved when three repeated measurement results were averaged. Concurrent validity between the two techniques was excellent for human wounds but poor for the smaller animal wounds, regardless of whether single or the average of three repeated surface area measurements was used. The computerized technique permits reliable and valid assessment of the surface area of both human and animal wounds.

Animals↗
PubMed2002

Three-dimensional imaging for the surgical treatment of idiopathic scoliosis in adolescents.

Scoliosis is not simply a lateral deviation of the spine but is a complex deformity of the entire trunk. Recent advances in 3-dimensional (3-D) imaging have improved our understanding of the 3-D nature of adolescent idiopathic scoliosis (AIS) and have resulted in the development of a new generation of spinal instrumentation. Stereophotogrammetry, computed tomography, magnetic resonance imaging and surface topography all have their specific 3-D applications and relevance in the clinical management of AIS. In the near future, novel 3-D imaging applications will provide tools to guide the surgeon in the planning, performance and evaluation of increasingly sophisticated and less invasive surgical procedures, thus improving the outcome of surgical treatment for AIS.

Adolescent↗
PubMed2002

Three-dimensional imaging in orthognathic surgery: the clinical application of a new method.

Many 3-dimensional (3D) techniques have been utilized to register and analyze the face in 3 dimensions, but each system has its own merits and disadvantages. C3D is a relatively new 3D imaging system that was developed to capture the 3D geometry of the face. Landmark identification on 3D facial models is facilitated by a software-based facial analysis tool developed by the authors. The reproducibility of landmark identification was high for 20 of the chosen points (standard deviations of repeated placements of landmarks around their centroids were 0.5 mm or less). The method is useful in studying facial soft tissue changes following orthognathic surgery and other types of facial surgery, as well as assessing facial soft tissue growth and development of the craniofacial complex.

Cephalometry↗
PubMed2002

3D stereophotogrammetric image superimposition onto 3D CT scan images: the future of orthognathic surgery. A pilot study.

The aim of this study was to register and assess the accuracy of the superimposition method of a 3-dimensional (3D) soft tissue stereophotogrammetric image (C3D image) and a 3D image of the underlying skeletal tissue acquired by 3D spiral computerized tomography (CT). The study was conducted on a model head, in which an intact human skull was embedded with an overlying latex mask that reproduced anatomic features of a human face. Ten artificial radiopaque landmarks were secured to the surface of the latex mask. A stereophotogrammetric image of the mask and a 3D spiral CT image of the model head were captured. The C3D image and the CT images were registered for superimposition by 3 different methods: Procrustes superimposition using artificial landmarks, Procrustes analysis using anatomic landmarks, and partial Procrustes analysis using anatomic landmarks and then registration completion by HICP (a modified Iterative Closest Point algorithm) using a specified region of both images. The results showed that Procrustes superimposition using the artificial landmarks produced an error of superimposition on the order of 10 mm. Procrustes analysis using anatomic landmarks produced an error in the order of 2 mm. Partial Procrustes analysis using anatomic landmarks followed by HICP produced a superimposition accuracy of between 1.25 and 1.5 mm. It was concluded that a stereophotogrammetric and a 3D spiral CT scan image can be superimposed with an accuracy of between 1.25 and 1.5 mm using partial Procrustes analysis based on anatomic landmarks and then registration completion by HICP.

Algorithms↗
PubMed2002

[Morphometric and stereologic nuclear values obtained from the study of a population suffering from nasopharyngeal carcinoma].

Computer nuclear morphometry and stereology are attractive methods because its objectivity and cheapness allowing histologic diagnosis when identifying minimal variations respectively the normality and also detect negligible disparities between anormal cells which could escape to the assessment of the pathologist. We present the data gained from several morphogenic and stereologic parameters resulting of measurements of tumoral cells procured from 40 patients with nasopharyngeal carcinomata. Middle values have been: nuclear area 27.70 microns 2; nuclear perimeter 20.80 microns; nuclear factor of form 0.81 microns; nuclear outline index 4.01; nuclear orientation angle 87.29 degrees; nuclear ellipsiticity 704.14; nuclear regularity 61.83; middle lineal length 4.30, middle linear distance 107.94; and nuclear volume 118.80 microns 3. Our series is the largest studied till now of all found in the literature. Comparison our data with those of previous publications.

Carcinoma, Squamous Cell↗
PubMed2000

Bond strengths and patterns of failure of a zinc polycarboxylate cement on surface-treated gold alloys.

The study investigated the shear strengths and fracture characteristics of a zinc polycarboxylate cement on three sets of type III gold alloy bars whose surfaces were modified by alumina blasting, heat treatment and tin plating respectively. Each set comprised 20 bars with similarly treated surfaces, cemented in pairs with the polycarboxylate cement and stored in water at 37 degrees C for 48 hours. The cement bond was then stressed to failure by application of forces in shear mode and the bond strength was determined. The mean bond strength for each type of treated gold alloy surface was calculated and then compared with the others by way of statistical analysis. The failed surfaces were observed and photographed with a stereophotomicroscope for subjective evaluation of the character of the failed surfaces. The strongest bonds were formed on the alumina-blasted surfaces where 70% of the bonds failed in an adhesive-cohesive fashion. The weakest bonds were formed on the tin-plated surfaces where cement failure was entirely adhesive. Bond strengths on the heat-treated surfaces were intermediate and a cohesive failure pattern was observed on 80% of the specimens. The differences in bond strengths on the three surfaces were statistically significant.

Adhesiveness↗
PubMed2000

[The clinical application of stereography in laryngology with "the three-dimensional reconstruction system of medical faultage photograph"].

OBJECTIVE: To study the value of the clinical application of stereography in laryngology. METHODS: Taken by Microtek E6 scanner, the CT faultage images were inputted in personal computer and reconstructed to a three-dimensional stereograph by "the three-dimensional reconstruction system of medical faultage photograph". The software was compiled using IDL5.2, a complete, integrated software environment for data analysis, visualization and application. RESULTS: The three-dimensional laryngeal graph could be incised in random, displayed in optional degree, and was rotatable, semitransparent and measurable. The tumor could identified be identified by a special color and revealed through translucent parenchyma and cartilage. Reconstruction stereographs of laryngeal and hypopharyngeal cancer of 26 patients were investigated. CONCLUSION: It is convenient for popularization because the three-reconstruction process is built on a personal computer without the need of any equipment for image acceleration. It is very helpful for ENT surgeon to define the range of the tumor, to fix on surgical pattern accurately and to anticipate the operational course.

Adult↗
PubMedDate not supplied

Stereology of the pterygopalatine ganglion of the rat.

The right pterygopalatine ganglia (PG) of 9 male Wistar-strain rats were dissected, embedded in Epon (3 specimens) or paraffin (6 specimens), and prepared for stereological examination under light microscopy. The perikarya were quantitatively characterized, and the ganglionic volume was determined. Stereology is an efficient method for the quantitative evaluation of the perikarya of the PG. The results(expressed as mean +/- standard deviation) were: a) areal fraction occupied by the perikarya = 53.8 +/- 7.4%; b) the perikaryal surface area per volume = 0.101 +/- 0.013 microns-1; c) the number of perikarya per volume x 10(-5) = 5.26 +/- 0.99 microns-3; d) the mean profile area of the perikarya (apk) = 505.93 +/- 78.29 microns 2; e) the mean perikaryal volume (vpk) = 9,179.33 +/- 1,533.52 microns 3; and f) the ganglionic volume = 0.210 +/- 0.127 mm3. The low coefficient of variation the apk and vpk values suggests the presence of only one population of neurons in the PG of the rat. The number of perikarya in the PG is about 11,046 per ganglion. As compared to analogous data in the otic ganglion of the rat, the PG did not show statistically significant stereological differences, but the relatively higher number of neurons found in the PG is probably associated with the higher functional activity of this ganglion.

Animals↗
PubMed1992

[Stereological study of the fat cells in bone marrows with a heterogeneous distribution of adipose tissue].

PURPOSE: 1) To analyze to what extent the fat tissue fraction of the human bone marrow with heterogeneous distribution depends on size and number of adipocytes. 2) To infer the influence of local factors on the two aforementioned parameters. MATERIAL AND METHODS: The material was made up of 15 specimens of bone marrow biopsy with markedly heterogeneous distribution of fat tissue, alternating normal or hyperplastic zones (area I) with aplastic ones (area II). The method of study was the stereological technique on plastic-embedded specimen sections. RESULTS: In the area II, with a fat tissue fraction markedly higher than in area I, both adipocyte number and size were significatively increased. The fat tissue fraction difference (Dif FRGR) between both areas was significatively correlated with the difference of the adipocytes number (Dif Nv) but not of the size (Dif D). However, in multiple regression both Dif Nv and Dif D contributed significatively to Dif FRGR. CONCLUSIONS: Since the histopathological pattern investigated in this work represents a model caused by intervention of local factors, it can be concluded that these can modify both the size and number of adipocytes.

Adipose Tissue↗