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PubMed1996

Microcalcification clustering parameters in breast disease: a morphometric analysis of radiographs of excision specimens.

X-ray microradiography of surgically excised breast specimens offers the possibility of morphological characterization of calcifications. When combined with digital imaging techniques there exists added potential for obtaining valuable basic quantitative morphometric information regarding differences between microcalcifications in tissues exhibiting evidence of fibrocystic change, benign and malignant tumours. A total of 157 excised breast specimens from 84 patients were microradiographed using a Softex Super Soft X-ray unit and Kodak AA high resolution industrial film. A Quantimet 570C image analysis system was used to digitize and analyse the microradiographs. Of the 157 microradiographs, 51 (from 30 patients) revealed microcalcification clusters. The existence of significant differences between the three identified categories of tissue were indicated by clustering parameters. These included the number of particles per cluster, area of clusters, maximum distance to nearest neighbour, and geometric mean distance to nearest neighbour. The distribution pattern index (DPI), another of the clustering parameters used in this study, has been observed to be a particularly powerful discriminator. The value for fibrocystic change was found to be significantly smaller (0.514) than that for benign tumour (0.796) whilst that for benign tumour was observed to be significantly larger than that for malignant tumour (0.604) at a p-value of less than 0.05 (Kruskal-Wallis one-way analysis of variance).

Adolescent↗
PubMed1993

Megaoesophagus in rats: a clinical, pathological and morphometrical study.

Megaoesophagus was observed in 82 Long-Evans rats aged 3-32 months. Clinically, the hair was coarse, the neck distended, the mouth opened, wetted by saliva and soiled by bedding material, and the respiration characterized by tachypnoea and inspiratory crackles. By radiography, after barium administration, the oesophagus was seen to be dilated and filled with impacted dry food in the precardial region. The size of the dilatation varied depending on the oesophageal region and reached a diameter of 12 mm in the most severe case. Histologically, the muscular layers of the dilated portions showed focal inflammation and single fibre necrosis. Each affected oesophagus had (1) an increased circumference and radius and a reduced number of myenteric ganglion cells in both the thoracic and abdominal portions, and (2) a decreased thickness of the muscular layers in the thoracic portion and at the level of the cardia. A simple geometrical model showed that the reduced ganglion cell number was not due to a change in shape of the dilated oesophagus. Since no sign of infectious disease was found in these animals, and rats of other strains kept at the same time under the same conditions were not affected, a hereditary aetiology is suggested.

Animals↗
PubMed1998

A neural network approach to the analysis and classification of human craniofacial growth.

Planning of treatment in the field of orthodontics and maxillo-facial surgery is largely dependent on the individual growth of a patient. In the present work, the growth of 43 orthodontically untreated children was analysed by means of lateral cephalograms taken at the ages of 7 and 15. For the description of craniofacial skeletal changes, the concept of tensor analysis and related methods have been applied. Thus the geometric and analytical shortcomings of conventional cephalometric methods have been avoided. Through the use of an artificial neural network, namely self-organizing neural maps, the resultant growth data were classified and the relationships of the various growth patterns were monitored. As a result of self-organization, the 43 children were topologically ordered on the emerging map according to their craniofacial size and shape changes during growth. As a new patient can be allocated on the map, this type of network provides a frame of reference for classifying and analysing previously unknown cases with respect to their growth pattern. If landmarks are used for the determination of growth, the morphometric methods applied as well as the subsequent visualization of the growth data by means of neural networks can be employed for the analysis and classification of growth-related skeletal changes in general.

Adolescent↗
PubMed1998

Relation between zero-stress state and branching order of porcine left coronary arterial tree.

The left common coronary arterial trees of eight pig hearts were dissected. The zero-stress state (the state of the organ when the external loads are removed) of the coronary arteries was determined by first cutting the arteries into short, ring-shaped segments perpendicular to the longitudinal axis of the blood vessel and then making a radial cut. This procedure caused the ring to open into a sector whose opening angle (theta), internal and external lengths (circumferences), and wall thickness were measured. Morphometric and theta data were organized in the framework of a diameter-defined Strahler system. We investigated 4 rings from the left common coronary artery (LCCA), 185 from the left anterior descending artery (LAD) and its branches, and 159 from the left circumflex artery (LCX) and its branches. The inner circumferences of the rings ranged over six orders for the LAD arterial tree and five orders for the LCX arterial tree, corresponding to a diameter range of about one order of magnitude for both arteries. theta demonstrates viscoelastic behavior and was measured 30 min after cutting. Our results show that the inner and outer circumference and the wall thickness increase as geometric sequences with the order number. theta is found to decrease linearly toward the smaller orders with a slope of 7.3 degrees/order in the range of the six largest orders. Strain calculations showed that the inner part of the arterial wall is in compression, whereas the outer part of the wall is in tension in the no-load (zero transmural pressure) state. This study provides basic data on the zero-stress state that are necessary for understanding the mechanics of the coronary artery.

Animals↗
PubMed1989

Structural changes in the tracheae of preterm lambs induced by ventilation.

Compliant immature airways sustain significant deformation following positive pressure ventilation. To evaluate the structural changes induced by in vivo positive pressure ventilation, tracheae of preterm lambs (107-116 d gestational age) were studied histologically. Nonventilated (group I: n = 7) and ventilated (group II: n = 7) tracheal segments were excised and studied by histologic and morphometric techniques. Computerized image analysis was used to measure dimensions of tracheal wall components and of the tracheal section. The circumference, diameter, and cross-sectional area of the section as well as the length of the trachealis muscle were significantly greater; although the thickness of the muscle and cartilage were seen to be significantly lower in group II sections compared to group I sections. Also, in comparison to group I, in group II sections there was lesser overlap of the posterior free ends of tracheal cartilage and the epithelial layer was flattened and focally abraded. Our findings demonstrate structural changes in the airway of preterm animals and characterize alterations in the geometric arrangement of muscle and cartilage after PPV. These results suggest possible structural mechanisms for the functional changes seen during and subsequent to mechanical ventilation.

Animals↗
PubMed2001

Morphometric study of the human lumbar spine for operation-workspace specifications.

STUDY DESIGN: The anatomy of the lumbar vertebrae of 55 patients was measured by use of data provided by computed tomography. On the basis of these measurements, the location of puncture points and the orientation of the surgical instruments for pedicle, vertebral body, and disc entry points were calculated for open as well as percutaneous surgery. OBJECTIVE: Normal anatomic variations of the lumbar spine were investigated to define the workspace for several spinal procedures and to define the workspace of a robot designed to guide the physician during those procedures. SUMMARY OF BACKGROUND: Several comprehensive studies of vertebrae dimensions have been conducted in the past, but they lack several dimensions that are needed to determine the exact location of the entry point and orientation of the tool, in particular when a computerized guidance system is used. METHODS: Fifty-five spinal columns (L1-L5, total 250 vertebrae) were measured by computed tomography. These data provide geometric relations that determine entry points and tool orientations for different spinal interventions. RESULTS: The workspace for spinal operations was defined on the basis of anatomic data taken from computed tomography scans. The data included 15 measurements for each vertebra that defined its shape. The processed data provided puncture points for several spinal procedures in both open and percutaneous surgery. CONCLUSIONS: This study provides additional information on vertebral structure needed to calculate accurately the entry point and tool orientation in various spinal procedures. These statistical data are also valuable for model and implant designs and for workspace specifications for a robot-assisted surgery system.

Adult↗
PubMed1994

Morphometry of arterioles and capillaries in hearts of senescent mice.

OBJECTIVE: The aim was to characterise quantitative changes in the coronary arterioles and capillaries with aging in mice. METHODS: Morphometric analysis of the coronary resistance vessels was carried out in 12 "young" mice (63 days) and 11 "old" mice (650 days). RESULTS: Compared to hearts from young mice, those from senescent mice were heavier, contained less water, and differed in several variables characterising terminal vessels. The main changes were a decreased capillary and arteriolar density, increased heterogeneity of capillary spacing, and larger arterioles with thicker walls. CONCLUSIONS: Aging of the murine myocardium is characterised by important changes at the level of the terminal vascular bed, the most prominent being a decrease in capillary and arteriolar density. The decrease in arteriolar density is most prominent in the classes of smallest vessels. All these changes represent an impairment of geometrical conditions for the oxygen supply to the myocardial tissue.

Aging↗
PubMedDate not supplied

Effects of image orientation on the comparability of pediatric brain volumes using three-dimensional MR data.

PURPOSE: The purpose of this study was to examine the comparability of morphometric measurements made on pediatric data sets collected at five scanner locations, each using variations on a 3D spoiled gradient-recalled echo (SPGR) pulse sequence. METHOD: Archived MR data from 60 typically developing children were collected and separated into seven groups based on the pulse sequence used. A highly automated image-processing procedure was used to segment the brain data into white tissue, gray tissue, and CSF compartments and into various neuroanatomic regions of interest. RESULTS: Volumetric comparisons between groups revealed differences in areas of the temporal and occipital lobes. These differences were observed when comparing data sets with different image orientations and appeared to be due to partial volume averaging (PVA) and susceptibility-induced geometric distortions. CONCLUSION: Our results indicate that slice selection and image resolution should be controlled in volumetric studies using aggregated data from multiple centers to minimize the effects of PVA and susceptibility-induced geometric distortions.

Adolescent↗
PubMed2000

Morphometric and mechanical properties of femora in young adult male turkeys with and without femoral fractures.

Morphologic and torsional mechanical properties of femora were evaluated in three groups of turkeys to determine whether turkeys that incurred femoral fracture have different radiographic, morphologic, and torsional mechanical properties than do turkeys without femoral fracture, and if body weight was a factor differentiating affected and nonaffected turkeys. Nine turkeys with unilateral femoral fractures and nine turkeys without fractures from Farm A were compared with a group of nine age and genetically matched turkeys from Farm B. Turkeys from Farm A were 10 to 25% heavier (26.2+/-0.9 kg) and turkeys from Farm B were 10% lighter (18.2+/-0.9 kg) than expected breed standards. Femoral length, cortical thickness, medullary diameter, and diaphyseal curvature were measured from craniocaudal and lateromedial radiographs. One intact femur from each of five turkeys with a contralateral femoral fracture (Farm A), nine unaffected turkeys from Farm A, and nine turkeys from Farm B were subjected to failure in a torsion test. Geometric and mechanical results were compared. Turkeys from Farm A had a thicker cortex and a smaller medullary diameter than turkeys from Farm B. Turkeys from Farm A had significantly lower torsional stiffness and failure torque values compared with turkeys from Farm B, when differences in body weight were accounted for (analysis of covariance, P < 0.05). Mechanical failure torque calculated from geometric values suggests that organic or inorganic material arrangement and composition may be responsible, in part, for differences between groups. Femoral fractures may be associated with insufficient skeletal adaptation to heavy body weight.

Animals↗
PubMed2003

A hybrid 3D watershed algorithm incorporating gradient cues and object models for automatic segmentation of nuclei in confocal image stacks.

BACKGROUND: Automated segmentation of fluorescently-labeled cell nuclei in 3D confocal microscope images is essential to many studies involving morphological and functional analysis. A common source of segmentation error is tight clustering of nuclei. There is a compelling need to minimize these errors for constructing highly automated scoring systems. METHODS: A combination of two approaches is presented. First, an improved distance transform combining intensity gradients and geometric distance is used for the watershed step. Second, an explicit mathematical model for the anatomic characteristics of cell nuclei such as size and shape measures is incorporated. This model is constructed automatically from the data. Deliberate initial over-segmentation of the image data is performed, followed by statistical model-based merging. A confidence score is computed for each detected nucleus, measuring how well the nucleus fits the model. This is used in combination with the intensity gradient to control the merge decisions. RESULTS: Experimental validation on a set of rodent brain cell images showed 97% concordance with the human observer and significant improvement over prior methods. CONCLUSIONS: Combining a gradient-weighted distance transform with a richer morphometric model significantly improves the accuracy of automated segmentation and FISH analysis.

Algorithms↗
PubMed2006

A novel quantitative cross-validation of different cortical surface reconstruction algorithms using MRI phantom.

Cortical surface reconstruction is important for functional brain mapping and morphometric analysis of the brain cortex. Several methods have been developed for the faithful reconstruction of surface models which represent the true cortical surface in both geometry and topology. However, there has been no explicit comparison study among those methods because each method has its own procedures, file formats, coordinate systems, and use of the reconstructed surface. There has also been no explicit evaluation method except visual inspection to validate the whole-cortical surface models quantitatively. In this study, we presented a novel phantom-based validation method of the cortical surface reconstruction algorithm and quantitatively cross-validated the three most prominent cortical surface reconstruction algorithms which are used in Freesurfer, BrainVISA, and CLASP, respectively. The validation included geometrical accuracy and mesh characteristics such as Euler number, fractal dimension (FD), total surface area, and local density of points. CLASP showed the best geometric/topologic accuracy and mesh characteristics such as FD and total surface area compared to Freesurfer and BrainVISA. In the validation of local density of points, Freesurfer and BrainVISA showed more even distribution of points on the cortical surface compared to CLASP.

Algorithms↗
PubMed1984

The lysosomal toxicity of aminoglycosides: a morphometric approach.

Lysosomes of kidney proximal tubule cells have been described as an early target involved in aminoglycoside-induced nephrotoxicity. These organelles concentrate these molecules and are overloaded with osmiophilic lamellar material. Biochemical alterations of lysosomes have already been described. In this study 6 aminoglycosides were given i.p. at the doses of 10 and 50 mg/kg for 4-7-15 days. A morphometric study of the lysosomal system of rat kidney proximal tubules is described first using Delesse's principle on electron micrographics. After aminoglycoside treatment, lysosomal volume rose from 3.3% in controls up to 10% or more of the cell volume. Concomitantly lysosomes were overloaded with myeloid bodies up to 50% or more of their own volume. Individual measurements of lysosome sections were performed on micrographics: perimeter and area. Size distributions were compared to each other using the Kolmogorov-Smirnov statistical test. Since the observed distribution could not be compared with a normal, Poisson, or any other theoretical distribution, the size distribution of perimeters has been successfully likened to a sum of individual normal subpopulations, the means of which follow a geometrical progression of rate square root 2 from a constant value of 1.23 micron, with standard errors of 15% of their respective mean value. When converted to membrane area values the progression rate becomes 2 and suggests fusion of identical size lysosomes during their intracellular life.

Animals↗
PubMed1990

Determination of the extracellular tortuosity in nuclear layers of the central nervous system by resistance measurements on a geometrical model.

The electrical resistivity of nuclear layers within CNS tissues is simulated by a densely packed array of glass spherules with a thin silver layer on their surfaces. Various mean spherule diameters and different thicknesses of the silver layer are tested; the relations between spherule diameter and thickness of silver mantle are in the same range as those between cell soma diameters and width of the extracellular clefts. Measuring the contribution of the silver layers to the total volume--corresponding to the extracellular volume fraction alpha within CNS tissues--and the resistance of columns of silvered spherules, tortuosity factors lambda 2 are calculated. Means of lambda 2 are found to vary within 5.6 and 9.2, independent of both spherule diameters and thickness of the silver layer, but strongly dependent on the packing density of the spherules. This latter dependence is described by a simple formula. These results are used to calculate the resistivities of the nuclear layers of the retina and of the granular layer in the hippocampal area dentata, based on morphometric data gained from own studies and literature reports, respectively. It is shown that such layers with densely packed cells express very high resistivity because of both low extracellular volume fraction and high tortuosity. Implications for current source density analyses, and for pathological events like epileptogenesis, are discussed. In an appendix, an analytical solution of the problem is given for the case of a cubic array of surface-conducting spheres.

Animals↗
PubMed1988

Mantle zone lymphoma: a morphometric comparison with centrocytic and immunocytic lymphomas and reactive secondary follicles.

Nuclear size and shape of lymphoid cells were evaluated morphometrically in the mantle zone lymphoma, immunocytic lymphoma, and centrocytic lymphoma, and were compared with those of reactive secondary follicles. Shape factors (forms Ar, Ell, Pe, and Dia) have been used to quantitatively define the most frequent nuclear profiles. One of the testing sets consisted of the nuclei of the light, dark, and mantle regions of reactive nodes, as well as those of the centrocytic lymphoma, immunocytic lymphoma, and the mantle-fashion growth lymphoma. Another testing set was made up of only the three types of lymphoma and was used for evaluating the variability of shapes within these groups by means of a pattern recognition algorithm. The content of reactive T lymphocytes was assessed in all cases by immunohistochemistry. The results of transforming centroid values into geometric shapes by computer modelling indicated that only minor geometric differences existed between the a priori qualitatively chosen nuclear types and those modeled a posteriori by computer. All the nuclear types were found in each of the reactive regions and in each of the lymphomas. However, highly significant differences of distribution were detected among the three categories of lymphoma and between each reactive region and each lymphoma. The cases of centrocytic lymphoma showed constant findings in terms of nuclear composition, while lymphomas with mantle-fashion growth and the examples of immunocytic lymphoma showed significant variability. These observations confirm that the centrocytic lymphoma represents a distinct entity, although its normal counterpart is still unknown, and question the view that the immunocytoma and the mantle zone lymphoma correspond to homogenous categories of non-Hodgkin's lymphomas. In addition, since all the qualitatively and quantitatively detected nuclear types were found in all the reactive regions and in all the lymphomas, albeit with different distributions, it has to be assumed that only numerical differences exist among the various lymphomas and the reactive regions.

Adult↗
PubMed1994

Fractal geometric analysis of material from molar and non-molar pregnancies.

Histological sections from 25 non-molar pregnancies, nine partial hydatidiform moles, and 16 complete hydatidiform moles were examined (diagnosis was taken as the consensus of seven experienced histopathologists) and the fractal dimension was measured using a box-counting method implemented on a microcomputer-based image analysis system. The fractal dimensions of the different diagnostic categories were normally distributed with a mean of 1.50 for non-molar pregnancies, 1.44 for partial moles, and 1.42 for complete moles. All the measured fractal dimensions were greater than the topological dimension (1), demonstrating that the specimens had a fractal element to their structure. There was a significant difference between the fractal dimensions of non-molar pregnancies and complete moles (P = 0.0005), but not between partial moles and non-molar pregnancies (P = 0.0823) or complete and partial moles (P = 0.4400). Using the fractal dimension to predict the histopathological diagnosis assigned 56 per cent of the cases to the correct category with a kappa statistic of 0.26, so the fractal dimension, used alone, is not a useful morphometric discriminant in the diagnosis of molar and non-molar pregnancy.

Female↗
PubMed2002

Ventricular remodeling and diastolic myocardial dysfunction in rats submitted to protein-calorie malnutrition.

The effects of protein-calorie malnutrition (PCM) on heart structure and function are not completely understood. We studied heart morphometric, functional, and biochemical characteristics in undernourished young Wistar rats. They were submitted to PCM from birth (undernourished group, UG). After 10 wk, left ventricle function was studied using a Langendorff preparation. The results were compared with age-matched rats fed ad libitum (control group, CG). The UG rats achieved 47% of the body weight and 44% of the left ventricular weight (LVW) of the CG. LVW-to-ventricular volume ratio was smaller and myocardial hydroxyproline concentration was higher in the UG. Left ventricular systolic function was not affected by the PCM protocol. The myocardial stiffness constant was greater in the UG, whereas the end-diastolic pressure-volume relationship was not altered. In conclusion, the heart is not spared from the adverse effects of PCM. There is a geometric alteration in the left ventricle with preserved ventricular compliance despite the increased passive myocardial stiffness. The systolic function is preserved.

Animals↗
PubMed2004

Bidirectional shift in the cornu ammonis 3 pyramidal dendritic organization following brief stress.

The negative impact of chronic stress at the structure of apical dendrite branches of cornu ammonis 3 (CA3) pyramidal neurons is well established. However, there is no information available on the CA3 dendritic organization related to short-lasting stress, which suffices to produce long-term habituation or sensitization of anxiety behaviors and neuroendocrine responses. Here, we tested the effects evoked by brief stress on the arrangements of CA3 pyramidal neuron dendrites, and the activity-dependent properties of the commissural-associational (C/A) excitatory postsynaptic potentials (EPSPs). Adult male rats were socially defeated followed by 3 weeks without further treatment or as comparison exposed to a regimen of a social defeat every second day for the same time period. We assessed CA3 pyramidal neurons with somatic whole-cell recording and neurobiotin application in acute hippocampal slices. The results from morphometric analysis of post hoc reconstructions demonstrated that CA3 dendrites from repeatedly stressed rats were reduced in surface area and length selectively at the apical cone (70% of control, approximately 280 microm from the soma). Brief stress, however, produced a similar decrease in apical dendritic length (77% of control, approximately 400 microm from the soma), accompanied by an increased length (167% of control) and branch complexity at the basal cone. The structural changes of the dendrites significantly influenced signal propagation by shortening the onset latency of EPSPs and increasing input resistance (r=0.45, P<0.01), of which the first was significantly changed in repeatedly stressed animals. Both brief and repeated stress long-lastingly impaired long-term potentiation of C/A synapses to a similar degree (P<0.05). These data indicate that the geometric plasticity of CA3 dendrites is dissociated from repetition of aversive experiences. A double social conflict suffices to drive a dynamic reorganization, by site-selective elimination and de novo growth of dendrite branches over the course of weeks after the actual experience.

Adrenal Glands↗
PubMed1987

Simple elementary method for the quantification of focal liver lesions induced by carcinogens.

Quantification of focally arranged preneoplastic cell populations in the liver is relevant for numerous experiments. An easy-to-process elementary method is presented for the estimation of the number of foci per cm3 and the size distribution of the foci on the basis of classifying areas of the profiles on the histological section. Using geometrically decreasing size classes, we have obtained the formula: (Formula: see text) where Nn is the number of foci per unit of volume of the size class Kn, Fn is the number of profiles of the class Kn per surface unit and An and Bn are constants dependent on the selection of the boundaries of the size classes. The method presented provides results that are at least as accurate as the values for the numbers of foci per cm3 arrived at by other methods used so far, whereas the distribution of the focus volumes describes the real situation better. It is relatively easy to process the data collected from the section and this can also be done without specific programs developed for this purpose. The method is especially recommended for investigators who only occasionally deal with morphometric questions and are therefore not interested in more complicated methods.

Animals↗