SEARCH · PubMed Health

Results for “morphometry”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 379 records · Page 21Linked to original sources

PubMed1996

Neural isolation of the jejunoileum. Effect on tissue morphometry, mucosal disaccharidase activity, and tissue peptide content.

The aim of this study was to determine the effects of a model of intestinal extrinsic denervation on mucosal structure and function. Six dogs underwent in situ neural isolation of the jejunoileum (Group 2); six other dogs served as operated controls (Group 1), and five nonoperated dogs were naive controls (Group 3). Thirty-centimeter segments of proximal jejunum and distal ileum were excised before (time zero) and at 2 weeks and 8 weeks postoperatively in Groups 1 and 2, while similar regions were removed at time zero in Group 3. Tissues were analyzed for morphology with quantitative morphometry, mucosal disaccharidase activities (sucrase, maltase, and lactase), and tissue content of selected regulatory peptides in transmural, mucosa/submucosa, and muscularis regions. In situ neural isolation had no significant or consistent effects on morphology/morphometry or on mucosal disaccharidase activities. Tissue content of neuropeptide Y decreased markedly (P < 0.002) in all layers of the jejunal and ileal walls, but tissue content of vasoactive inhibitory polypeptide, substance P, cholecystokinin, neurotensin, met-enkephalin, neurokinin A, somatostatin, and calcitonin gene-related peptide demonstrated only minor changes. The physiologic effects of intestinal transplantation (extrinsic denervation and disruption of intrinsic, enteric neural continuity, and lymphatic drainage) have little effect on morphology, mucosal disaccharidase activity, and tissue content of most regulatory peptides. How these minor alterations might affect enteric function, however, needs to be investigated.

Animals↗

PubMed2000

Morphometry of the canine prostate vasculature.

Morphometric data of the tissue vasculature are fundamental to the development of models for blood perfused tissue mass and heat transfer. Vascular casts of six canine prostates were made and morphometry was performed on 14 transverse sections. The region sampled was restricted to the midsection within the parenchyma. General vascular features that were observed include the radially arranged arteries and veins within the parenchyma, the axially oriented periurethral venous plexae, and the parenchymal arteries ramifying less than the veins. The arterial and venous lumen diameters (mean +/- SD) are 84 +/- 31 (N = 42) and 125 +/- 51 (N = 117), respectively. The lengths for a single vessel generation are 2147 +/- 1196 microm (N = 14) and 1265 +/- 693 microm (N = 39) for the arteries and veins, respectively. Intervessel distances are 4056 +/- 2350 microm (N = 33) between arteries, 1526 +/- 982 microm (N = 330) between veins, and 1498 +/- 874 microm (N = 108) between arteries and veins. A simple vasculature model of evenly distributed vessels imbedded in tissue for heat transfer analysis was developed. The artery-artery distance being about three times that of the vein-vein distance suggested a rete-like configuration of arteries surrounded by veins. An effective distance of 1519 microm between vessels was used. Based upon this vasculature model, the vessel density was calculated to be 5.6 arteries/cm(2) and 44.5 veins/cm(2).

Animals↗

PubMed2000

Voxel-based morphometry--the methods.

At its simplest, voxel-based morphometry (VBM) involves a voxel-wise comparison of the local concentration of gray matter between two groups of subjects. The procedure is relatively straightforward and involves spatially normalizing high-resolution images from all the subjects in the study into the same stereotactic space. This is followed by segmenting the gray matter from the spatially normalized images and smoothing the gray-matter segments. Voxel-wise parametric statistical tests which compare the smoothed gray-matter images from the two groups are performed. Corrections for multiple comparisons are made using the theory of Gaussian random fields. This paper describes the steps involved in VBM, with particular emphasis on segmenting gray matter from MR images with nonuniformity artifact. We provide evaluations of the assumptions that underpin the method, including the accuracy of the segmentation and the assumptions made about the statistical distribution of the data.

Brain↗

PubMed2001

Voxel-based morphometry of herpes simplex encephalitis.

Voxel-based morphometry (VBM) is a powerful tool for analyzing changes in gray or white matter density of the brain. By using an automated segmentation procedure and standardized parametric statistics it avoids biases inherent in operator-dependent morphological operations (J. Ashburner and K. J. Friston, 2000, NeuroImage 11, 805-821). Since its introduction in 1995, VBM has been used to examine anatomical changes in a variety of diseases associated with neurologic and psychiatric dysfunction. Given the power of this technique for discerning subtle anatomical changes, we wanted to assess its performance on brains with gross structural abnormalities. Such results could have implications regarding the difficulties to be faced when examining other types of distorted brains (e.g., brains with changes due to degenerative disease). This report describes the use of VBM for examining individual and group changes in gray matter concentration in five patients who had recovered from herpes simplex encephalitis (HSE) compared with age- and sex-matched controls. Because HSE tends to affect a specific set of brain regions we thought that this would (1) provide an opportunity to assess the anatomical face validity of VBM, (2) allow us to assess the problems of this technique when used on distorted brains, and (3) provide an in vivo demonstration of the gray matter changes due to HSE. We found that, despite problems in normalizing and segmenting these severely distorted brains, VBM was able to identify correctly a number of the regional gray matter abnormalities in HSE. The results, while consistent with the well-known histopathology of the disease, also demonstrate potential difficulties with this method.

Adult↗

PubMed2001

"Voxel-based morphometry" should not be used with imperfectly registered images.

John Ashburner and Karl Friston (2000) introduced a standardized method of "voxel-based morphometry" (VBM) for comparisons of local concentrations of gray matter between two groups of subjects. Segmented images of gray matter from grossly normalized high-resolution images are smoothed and their group differences analyzed by the now-conventional voxelwise Worsley approach to Gaussian random fields of differences. This comment concerns an unfortunate interaction between the algorithm's spatial normalization and voxelwise comparison steps, whereby several obvious quantitative confounds are injected at the core of the inference engine the authors put forward. Specifically, the statistics of the resulting voxelwise comparisons are uninformative about group differences wherever the spatial normalization algorithm has failed to register on any robustly appearing image gradient. The method of Ashburner and Friston is defensible only far from all image gradients.

Artifacts↗

PubMed2001

Deformation-based morphometry and its relation to conventional volumetry of brain lateral ventricles in MRI.

Deformation-based morphometry (DBM) is a useful technique to detect morphological differences over the entire brain since it analyses positional differences between every voxel and a standard brain. In this report we compare DBM to semimanual tracing of brain ventricles in a population of 39 patients with schizophrenia. High-resolution T(1)-weighted magnetic resonance images were obtained and processed with DBM and interactive tracing software. We evaluate the validity of the DBM in two different approaches. First, we divide subjects into two groups based on the mean ventricular/brain ratios and compute statistical maps of displacement vectors and their spatial derivatives. This analysis demonstrates a striking consistency of the DBM and visual tracing results. We show that restricting the information about the deformation fields by computing the local Jacobian determinant (as a measure of volume change) provides evidence of the shape of ventricular deformation which is unavailable from ventricular volume measures alone. Second, we compute a mean measure of the Jacobian values over the entire ventricles and observe a correlation of r = 0.962 with visual tracing based ventricular/brain ratios. The results support the usefulness and validity of DBM for the local and global examination of brain morphology.

Adolescent↗

PubMed2002

Sexual dimorphism in the corpus callosum: a characterization of local size variations and a classification driven approach to morphometry.

We present two complementary quantitative approaches to the problem of characterizing morphometric variations between two distinct populations. The case presented focuses solely on local size variations, but the general method can easily be applied to other scalar morphometric quantities. The first method uses a statistical parametric map (SPM) to ascertain a P value, which indicates whether any statistically significant differences exist between the populations. The second method focuses on finding the best single measurement which can be used for classifying the two populations. For our case study midsagittal cross sections of the corpora callosa from a population of normal males and females are nonrigidly registered (spatially normalized) to an atlas. The resulting deformations are then used to ascertain (i) whether there are any statistically significant differences between the populations and (ii) whether these differences allow one to perform classification. We make use of the Jacobian of the deformation field and normalize it to account for overall volume changes allowing us to focus on differences which are more related to morphometry than scale. From the (SPM) approach to the problem we find evidence of statistically significant differences in the morphology between the populations. Using a linear discriminant function we find that these differences do not appear to be useful for classification. Thus, this dataset provides an example of how statistically significant effects may not be of much diagnostic value. They may be of interest to the research community, but of little value to the clinician.

Adult↗

PubMed2002

Voxel-based morphometry reveals increased gray matter density in Broca's area in male symphony orchestra musicians.

Broca's area is a major neuroanatomical substrate for spoken language and various musically relevant abilities, including visuospatial and audiospatial localization. Sight reading is a musician-specific visuospatial analysis task, and spatial ability is known to be amenable to training effects. Musicians have been reported to perform significantly better than nonmusicians on spatial ability tests, which is supported by our findings with the Benton judgement of line orientation (JOL) test (P < 0.001). We hypothesised that use-dependent adaptation would lead to increased gray matter density in Broca's area in musicians. Voxel-based morphometry (VBM) and stereological analyses were applied to high-resolution 3D MR images in male orchestral musicians (n = 26) and sex, handedness, and IQ-matched nonmusicians (n = 26). The wide age range (26 to 66 years) of volunteers permitted a secondary analysis of age-related effects. VBM with small volume correction (SVC) revealed a significant (P = 0.002) region of increased gray matter in Broca's area in the left inferior frontal gyrus in musicians. We observed significant age-related volume reductions in cerebral hemispheres, dorsolateral prefrontal cortex subfields bilaterally and gray matter density in the left inferior frontal gyrus in controls but not musicians; a positive correlation between JOL test score and age in musicians but not controls; a positive correlation between years of playing and the volume of gray matter in a significant region identified by VBM in under-50-year-old musicians. We suggest that orchestral musical performance promotes use-dependent retention, and possibly expansion, of gray matter involving Broca's area and that this provides further support for shared neural substrates underpinning expressive output in music and language.

Adult↗

PubMed2005

Acquisition-related limitations in MRI based morphometry.

Although significant effort has been spent over the past decades to develop innovative image processing algorithms and to improve existing methods in terms of precision, reproducibility and computational efficiency, relatively few research was undertaken to find out to what extent the validity of results obtained with these methods is limited by inherent imperfections of the input images. This observation is especially true for MRI based morphometry, which aims at precise and highly reproducible determination of geometrical properties of anatomical structures despite the fact that MR images are geometrically distorted. We here present (a) a method for characterization of site-specific geometrical distortions and (b) the results of a long term study designed to find out how precisely geometrical properties and morphological changes of brain structures can, in principle, be detected in images acquired with MRI scanners. Due to the long-term character of our study, our findings include effects resulting from limited hardware stability as well as from variations in patient positioning. Our results show that these effects can be strong enough to substantially confound MRI studies of small morphological changes.

Algorithms↗

PubMed1988

Morphometry of right ventricular papillary muscle in rat during development and regression of hypoxia-induced hypertension.

Morphometric analyses of the right ventricular papillary muscle, as well as measurements of right ventricular pressure and weight, were carried out in the rat during the development and recovery of hypoxic pulmonary hypertension. Animals were divided into hypoxic and normobaric control groups. The hypoxic rats were placed in hypobaric chambers for 1, 2, and 3 wks; and after 3 wks exposure, subgroups of hypoxic rats were allowed to recover in normoxia for 1 to 9 wks. Hematocrit (HCT) and right ventricular systolic pressure (RVSP) were measured prior to sacrifice. The heart was perfused, and the right ventricle (RV) was separated from the left ventricle and septum (LV+S) and weighed. The papillary muscles were dissected and processed for ultrastructural morphometry. Results showed that HCT, RVSP, and RV weight increased in the rats during the hypoxic exposure and then gradually returned to control levels after 3 to 4 wks of normobaric recovery. The papillary muscle of the hypoxic rats showed increased volume density of interstitium, increased diameter and cross sectional area of the cardiac myocytes, reduced volume density of mitochondria, and reduced mitochondria to myofilament ratio. During normoxic recovery, these morphometric indices returned toward control values at various periods of time ranging from less than 3 wks to 9 wks. The results indicate that the adaptive ultrastructural changes of the papillary muscle in RV hypertrophy paralleled the RVSP changes, and also demonstrate the reversibility of these changes in ambient oxygen.

Animals↗

PubMed1991

Morphometry of the corpus callosum in normal aging and Alzheimer's disease.

Changes of the human corpus callosum in normal aging and Alzheimer's disease were analysed by means of morphometry. A standardized computerized evaluation program was implemented allowing objective, quantitative and reproducible data. The various parts of the corpus callosum showed a different pattern of changes in normal aging as compared to Alzheimer's disease. In conclusion, in normal aging affects mostly the front-temporal interhemispheric fiber systems, whereas in Alzheimer's disease the parietotemporal commissural fibers are altered.

Aging↗

PubMed1994

Cell proliferation indices, morphometry and DNA flow cytometry provide objective criteria for distinguishing low and high grade bladder carcinomas.

Argyrophilic nucleolar organizer region (Ag-NOR) analysis, proliferating cell nuclear antigen (PC-NA/PC10) and MIB-1 immunohistochemistry, nuclear morphometry and DNA flow cytometry have been performed on formalin-fixed, paraffin-embedded biopsies from 50 patients with transitional cell carcinoma of the urinary bladder. The mean AgNOR count was 6.01 for the 17 grade 1 (G1), 7.59 for the 21 G2 and 13.33 for the 12 G3 carcinomas (p < 0.001). The mean PCNA score was 15.03% for G1, 24.04% for G2 and 40.01% for G3 cases (p < 0.001). The mean MIB-1 score was 11.31% for G1, 17.09% for G2 and 34.47% for G3 carcinomas (p < 0.001). The mean nuclear area was 35.53 microns2 for G1, 38.65 microns2 for G2 and 83.62 microns2 for G3 cases (p < 0.001). Aneuploidy rates were significantly higher (91.7%) in G3 than in G2 (42.9%, p < 0.01) or G1 cases (47.1%, p < 0.05) but not different for G1 versus G2 cases (p = 0.94). While many overlaps of values were seen between G1 and G2 tumours, no overlaps were found between G3 and G1/G2 tumours. Significant differences of values were also found between pTa and invasive tumours (p < 0.0001 for AgNOR count and PCNA score; p < 0.001 for MIB-1 score and mean nuclear area; p < 0.01 for DNA ploidy); however many overlaps were seen. Our findings indicate that the quantitative parameters obtained with different methods are associated with histological grade of bladder urotheliomas and may improve the grading reproducibility. In addition, the absence of overlaps between G3 and G2/G1 carcinomas supports the tendency to classify bladder urotheliomas in only two categories of malignancy.

Aneuploidy↗

PubMed1975

[Contribution to the morphometry of coronary arteriosclerosis (author's transl)].

In 94 cases with and without coronary arteriosclerosis or various cardiac diseases the coronary arteries were pressure fixed, filled with a mixture of barium sulfate and gelatine for coronary angiography and dissected in 1 cm long segments for morphometry. On consecutive cross sections of the three main branches of the coronary arteries the absolute area of lumen, intima and media as well as of the thickness of the intima and media were measured. From the numerous data of the coronary arteries different indices on coronary arteriosclerosis and by correlation to the heart weight also on coronary insufficiency had been calculated. Using these quantitative data age dependent intimal changes could be distinguished convincingly from cases with uncomplicated coronary arteriosclerosis and cases with hypertension or infarcts. Thus in forensic pathology comparative evaluations can be made in regard to the extent, severity and significance of acute and chronic coronary insufficiency.

Acute Disease↗

PubMed1985

Characterization of an oxygen-tolerant cell line derived from Chinese hamster ovary. Antioxygenic enzyme levels and ultrastructural morphometry of peroxisomes and mitochondria.

To study the cellular defense mechanism against oxygen toxicity, an oxygen-tolerant cell line from Chinese hamster ovary (CHO) was obtained by multistep adaptation to increased O2 levels. The hyperoxia-adapted (HA) cells were able to proliferate under an atmosphere of 99% O2/1% CO2, an O2 tension lethal to the parental (control) cells. When grown under normoxic conditions (20% O2/1% CO2/79% N2) the cells remained tolerant for at least 8 weeks, suggesting a genetic basis for the oxygen tolerance. Compared to the parental cells, the HA cells were irregularly shaped, had larger mitochondria, contained more lipid droplets and showed a reduced growth rate. Ultrastructural morphometry revealed a 1.8-fold (p less than 0.001) increase of the mitochondrial volume fraction in the HA cells, resulting from an increase in both number and average volume of the mitochondria. The volume fraction of peroxisomes was increased over two-fold in the HA cells, as appeared from a approximately 1.9-fold (p less than 0.001) increase in number and a 1.2-fold (p less than 0.025) increase in size. There was no evidence for ultrastructural damage in the HA cells. Specific activities of antioxygenic enzymes were considerably higher in the HA cells compared to controls: CuZn-superoxide dismutase, X 2.5; Mn-superoxide dismutase, X 2.1; catalase, X 4.0; glutathione peroxidase, X 1.9. Oxygen tolerance in CHO cells is therefore associated with increased levels of antioxygenic enzymes, confirming the proposed important role of these enzymes in the defense against oxygen toxicity.

Adaptation, Physiological↗

PubMed1985

Ultrastructural morphometry of parathyroid cells in rats of different ages.

Parathyroid glands of newborn to 1-year-old male Sprague-Dawley rats were fixed by perfusion or by immersion, and prepared for electron microscopy. Parathyroid glands fixed by immersion exhibited parenchymal cells with variable ultrastructure, indicating that these cells were in different stages of the proposed secretory cycle in parathyroid cells. In contrast, parathyroid cells of glands fixed by perfusion were uniform in ultrastructure, suggesting that all cells were in the same stage of secretory activity. Parathyroid glands of 3-, 4-, 6-, 8- and 10-week-old rats also were fixed by perfusion and analysed by electron-microscopic morphometry. These data demonstrated an increase in cell volume and in surface area of the membrane compartments concerned with parathyroid hormone secretion: these changes were not related to variations in serum calcium concentration. Both the qualitative observations and the quantitative data do not favour the idea of a secretory cycle in rat parathyroid cells.

Aging↗

PubMed1984

Effects of TRH and somatostatin on releases of prolactin and growth hormone in vitro by the pituitary of Poecilia latipinna. II. Electron-microscopic morphometry using automatic image analysis.

Pituitary glands from a teleost fish were incubated in the presence of the synthetic hypophysiotropic peptides, thyrotrophin-releasing hormone and somatostatin, in two media of different osmotic pressure. The effects on prolactin and growth hormone cells were detected by electron-microscopic morphometry with the aid of an image analyser. Thyrotrophin-releasing hormone caused changes in prolactin cell ultrastructure consistent with stimulated hormone release and, in the low osmotic pressure medium, appeared to increase synthetic activity. There was no effect on growth hormone cells. After somatostatin treatment, both synthesis and release in prolactin cells appeared to be inhibited, and there was an obvious inhibition of synthesis and release in growth hormone cells. The response of both cell types to somatostatin did not appear to be dependent on the osmotic pressure of the medium.

Animals↗

PubMed1994

Band 3 antagonists, p-azidobenzylphlorizin and DIDS, mediate erythrocyte shape and flexibility changes as characterized by digital image morphometry and microfiltration.

Two nonpenetrating membrane probes, p-azidobenzylphlorizin (p-AzBPhz) and 4,4'-diisothiocyano-2,2'-stilbene disulfonate (DIDS), have been shown in earlier studies to induce dose-dependent changes in red blood cell (RBC) shape and volume at the same low concentrations that inhibit anion transport. In the present work, these ligand-induced morphology and rheology changes were studied using video digital image morphometry (VDIM) and microfiltration techniques. The results of these experiments corroborate our earlier investigation. RBCs were filmed using a Nomarski optics microscope with video camera attachment and cell size and shape changes were computer analyzed using VDIM. Low microM p-AzBPhz or DIDS levels caused collapse of the cell's biconcave structure and cell flattening occurred within 1-2 sec after drug exposure. Higher doses of either agent converted cells to a new steady-state in which a concurrent limited increase in erythrocyte volume and blunt membrane protrusions were produced. These changes were reversed in less than 2 sec by washing the drug from the membrane. Both ligands increased the deformability of RBCs in a dose-dependent manner as determined by filtration through Nuclepore polycarbonate filters (3 microns pore diameter). The improvement in deformability of drug-treated sickle cells was much more dramatic than for normal cells at low p-AzBPhz concentrations. These results support our earlier conclusions that the ligands, through a common interaction with band 3, induce volume-associated cytoskeletal alterations which lead to changes in morphology and flexibility.

4,4'-Diisothiocyanostilbene-2,2'-Disulfonic Acid↗

PubMed1981

Ultrastructural morphometry of blastogenesis. II. Stimulated lymphocytes, the progeny of blast cells induced in vivo with DNCB.

As a companion to an earlier study, the morphometric attributes of stimulated (blast-derived) lymphocytes in mouse axillary lymph nodes have been established using stereological and autoradiographic methods. Blast transformation was induced in vivo with dinitrochlorobenzene (DNCB) and stimulated cells were labelled with tritiated thymidine. Random samples of cells were taken for light and electron microscopic morphometry. In comparison to the unstimulated lymphocyte, the stimulated cell increased in size and possessed a greater plasma membrane surface area. Increase in cell size was the result of increases in the volumes of all measured subcellular compartments both in the nucleus and the cytoplasm. Heterogeneity of the stimulated cell population precludes firm conclusions regarding the significance of all these ultrastructural changes, though alterations in cell surface are discussed in the context of known biochemical differences accompanying blastogenesis.

Animals↗