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Results for “computational morphology”

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At least 181 records · Page 10Linked to original sources

PubMed1992

[Morphological brain changes in senile depressions. A morphometric computed tomographic study].

The inner and outer cerebrovascular spaces visualized by CT were measured planimetrically in 34 patients (6 men, 28 women; mean age 70.7 years) with senile depression. The purpose was to ascertain whether computed tomography (CT) can detect morphological changes in the brain of patients with senile depression. Compared with a control group without evidence of neurological and psychiatric abnormalities (10 men; 33 women; mean age 70.8 years), there was an enlargement in the group with senile depression of the lateral ventricles (P less than 0.05), occipital sulci (P less than 0.05) and lateral sulci (P less than 0.01). There was no correlation with the duration of illness or the stage of depression. These findings point to the cerebral structural changes having already been present previously and argue against a progressive process of atrophy. In the case of senile psychiatric changes, cerebral morphological changes should be paid more attention, in addition to any results from research into psychosocial causes.

Aged↗

PubMed1996

Mesenteric plexiform neurofibroma: computed tomography appearance.

Gastrointestinal involvement in von Recklinghausen's disease is usually in the form of neurofibromas and leiomyomas. Very rarely, plexiform neurofibromas may be seen involving the bowel wall and myenteric plexus with secondary minor involvement of the mesentery. This report describes the computed tomography morphology of a plexiform neurofibroma extensively involving the mesentery with minor involvement of the bowel wall.

Child↗

PubMed1997

Evaluation of cell morphology by video recording and computer-assisted image analysis.

The aim of this study was to evaluate the effects of various cell culture conditions on cell morphology. Cell morphology was estimated by means of video recording and computer-assisted image analysis. Cell contours from the stored images of either live cells or fixed and stained cells were determined automatically, and cellular area, form factor, and average cell brightness were calculated. Using the mouse fibroblastoid L 929 cell line (L-cells) and the rat glioma BT4C cell line, it was found that a number of methodological parameters strongly affected cell morphology. These included confluency of cells before dissociation, dissociation procedure, cell seeding density, cultivation time, and culture substratum. The substratum, particularly collagen type I and fibronectin, profoundly affected cell morphology. Using drugs affecting cytoskeletal organization or cell substratum interactions, it was shown that average cell brightness was a valuable parameter for estimation of cellular attachment. Cytochalasin D, which impairs actin filaments, caused a dramatic increase in the average cell brightness in both cell lines. Nocodazole, which depolymerizes microtubules, mainly affected the L-cells, whereas the BT4C-cells were largely unaffected, indicating that microtubules were morphological determinants for the former cell line but not for the latter. When cells were grown on fibronectin, an RGD-peptide only affected L-cell attachment, indicating that BT4C-cells only expressed low (if any) amounts of RGD recognizing integrins. The interassay precision of the employed procedure depended on culture substratum; the coefficients of variation ranged from 7-24%. Lowest variations in area determination were found for cells grown on fibronectin. The coefficient of variation of form factor determinations was generally around 20%, independent of substrata and culture time.

Animals↗

PubMed2004

[Thoraxsonography--Part 1: Chest wall and pleura].

The detection of lymph nodes and a careful interpretation of dignity is one of the main indications for chest wall sonography. Palpable unclear masses of the chest wall can undergo US guided puctures very easily. Either rib and sternum fractures are detectable very sensitively. In addition to the more sensitive detection than in normal X-ray also accompanying soft parts processes, pleural effusions and haematomas can be visualised. Despite the physical laws of ultrasound, approximately 70% of the pleural surface can be accessed by sonography. The normal parietal pleural can be visualized and delineated from circumscribed as well as diffuse pathological thickening. The normal visceral pleura is hidden by the total reflection at the surface of the aerated lung. Sonographic evidence of a pleural effusion can be obtained from 5 ml onwards and is much more sensitive than a chest X-ray, especially in supine position; false positive findings are not encountered. A more accurate estimation of the quantity of effusion can be made. Exudates are echogenic in one third of cases. Pleural thickening, nodular changes in the pleura, septa, and the formation of the quality of effusion can be made. Exual exudates, whereas transudates are always anechoic. Pleural metastases are characteristically hypoechoic and nodular-polypoid. Pleural mesotheliomas can be delineated nearly equally well on sonograms and on computed tomography. Morphological and, in particular, functional diagnosis of the diaphragm by means of sonography is both reliable and convincing.

Diagnosis, Differential↗

PubMed2001

Whole-body 18F dopa PET for detection of gastrointestinal carcinoid tumors.

PURPOSE: To evaluate fluorine 18 (18F) dopa positron emission tomography (PET) in comparison with established imaging procedures in gastrointestinal carcinoid tumors. MATERIALS AND METHODS: After evaluation of the normal distribution of 18F dopa, 17 patients with histologically confirmed tumors were examined with 18F dopa PET. Results of 2-[fluorine 18]fluoro-2-deoxy-D-glucose (FDG) PET, somatostatin-receptor scintigraphy, and morphologic imaging (computed tomography and/or magnetic resonance imaging) were available for all patients. Results of the procedures were evaluated by two radiologists and two nuclear medicine specialists, whose consensus based on all available histologic, imaging, and follow-up findings was used as the reference standard. RESULTS: Ninety-two tumors were diagnosed: eight primary tumors, 47 lymph node metastases, and 37 organ metastases. 18F dopa PET led to 60 true-positive findings (seven primary tumors, 41 lymph node metastases, 12 organ metastases); FDG PET, 27 (two primary tumors, 14 lymph node metastases, 11 organ metastases); somatostatin-receptor scintigraphy, 52 (four primary tumors, 27 lymph node metastases, 21 organ metastases); and morphologic imaging, 67 (two primary tumors, 29 lymph node metastases, 36 organ metastases). This resulted in the following overall sensitivities: 18F dopa PET, 65% (60 of 92); FDG PET, 29% (27 of 92); somatostatin-receptor scintigraphy, 57% (52 of 92); morphologic procedures, 73% (67 of 92). Although the morphologic procedures were most sensitive for organ metastases, 18F dopa PET enabled best localization of primary tumors and lymph node staging. CONCLUSION: 18F dopa PET is a promising procedure and useful supplement to morphologic methods in diagnostic imaging of gastrointestinal carcinoid tumors.

Adult↗

PubMed1984

Computed tomographic scan cerebral asymmetries and morphologic brain asymmetries. Correlation in the same cases post mortem.

We examined the relationship between computed tomographic (CT) scan hemispheric asymmetries and postmortem brain asymmetries of the planum temporale region in the same 15 subjects (right-handed men). A significant correlation was found between occipital length asymmetry visible on the CT scan slice at the level of the bodies of the lateral ventricles and planum temporale length asymmetry found at autopsy. We believe that some CT scan asymmetries may be indexes of underlying anatomic brain asymmetries. These anatomic brain asymmetries, in turn, may underlie some functional asymmetries observed in humans, especially those asymmetries related to language.

Adult↗

PubMed2007

[Subdental synchondrosis. Computed tomographic and histologic investigation on morphological aspects of fracture at the base of the dens in 36 human axis specimens].

BACKGROUND: During development of the axis, four different ossification centers are formed. The two cranial ossification centers are demarcated from the ossification center of the vertebral corpus by a subdental synchondrosis. During further development the subdental synchondrosis--which is thought to close spontaneously--might not close completely, which leads to the necessity for differentiating synchondrotic remnants from a fracture at the base of the dens (type II according to Anderson and D'Alonzo). RESULTS: To characterize the architecture of the axis with particular attention to the subdental synchondrosis, the axis was harvested from 36 age- and gender-matched patients covering the human aging process from adolescence to senescence. In all specimens bone mineral density (BMD) was measured by peripheral quantitative computed tomography (pQCT). Morphological analysis after undecalcified processing of all specimens revealed a persistency of the subdental synchondrosis in 87% of all patients. Histological characterization of the subdental synchondrosis showed a cartilaginous structure interspersed with focal mineralization. Furthermore, static histomorphometric analysis revealed that trabecular bone volume and cortical thickness were significantly reduced within the base of the axis as compared to the dens and the corpus, respectively. CONCLUSION: Taken together, these results provide evidence that the base of the axis is a structurally distinct region. Besides well-recognized biomechanical aspects, these results suggest that the structure of the base of the axis might contribute to the occurrence of fractures of the axis and offer an additional explanation for the observation of nonunion after type II dens fractures.

Adolescent↗

PubMed1992

Tubule-tubule and tubule-arteriole contacts in rat kidney distal nephrons. A morphologic study based on computer-assisted three-dimensional reconstructions.

BACKGROUND: Functional investigations of the tubulo-glomerular feedback mechanism have indicated the existence of a contact between the distal nephron and the macula densa region. The structural justification of such a contact is investigated. EXPERIMENTAL DESIGN: Tubule-tubule and tubule-arteriole contacts were investigated in distal nephrons from normal rat kidneys. Computer-assisted three-dimensional reconstructions of distal nephrons were made from serial sections of renal cortical tissue and selected sections were examined by electron microscopy. RESULTS: In 14 of 15 reconstructed nephrons, the distal convoluted tubule or the connecting tubule approached the macula densa region. A wall-to-wall contact between two tubules corresponding to a three-dimensional distance below 28 microns between the axes of the two tubules was found in only five of the reconstructed tubules. The distal nephron contacts to afferent and efferent arterioles of the same nephron were also examined. The efferent arteriole revealed no consistent contacts but the afferent arteriole contacted the distal convoluted tubule/connecting tubules consistently in all 10 of the superficial nephrons and in 3 of 5 midcortical nephrons. Electron microscopy confirmed a close contact between the distal tubule and the afferent arteriole in superficial nephrons and small nerves were often found at or near the site of contact, but the morphology at the site of contact was not unique. The arteriole contacts were made with late distal convoluted tubules, connecting tubules, or cortical collecting ducts. CONCLUSIONS: In conclusion, the present study shows that tubule-tubule contacts are inconsistent between the macula densa region and the distal nephron but that the tubule-afferent arteriole contact is consistent and close in superficial nephrons. This morphology is compatible with the existence of a feedback mechanism between the superficial distal nephron and the afferent arteriole, apart from the one located at the juxtaglomerular apparatus.

Animals↗

PubMed2001

Predictive value of bone mineral density and morphology determined by peripheral quantitative computed tomography for cancellous bone strength of the proximal femur.

Peripheral quantitative computed tomography (pQCT) is an established diagnostic method for assessment of bone mineral density in the diagnosis of osteoporosis. However, the capacity of structural parameters of cancellous bone measured by high-resolution computed tomography remains to be explored. In 33 patients, bone mineral density (BMD) of the proximal femur was measured in vitro by pQCT using cylindrical biopsies from the intertrochanteric region harvested before the implantation of an artificial hip joint. By digital image analysis of CT scans, parameters derived from histomorphometry describing the microarchitecture of cancellous bone were measured. The biopsies were also loaded to failure by an uniaxial compression test to determine the biomechanical parameters, Young's modulus, strength, and maximum energy absorption (E(max)). Strong correlations were found for BMD vs. mechanical parameters (r = 0.73 for Young's modulus, r = 0.82 for strength, and r = 0.79 for E(max); p < 0.001, n = 29). The morphological parameters, bone volume per trabecular volume (BV/TV), apparent trabecular thickness (app.Tb.Th), apparent trabecular separation (app.Tb.Sp), and trabecular number (Tb.N), correlated significantly with all mechanical parameters. The combination of morphological parameters with BMD in a multivariate regression model led to an overall, but only moderate, increase in R(2) in all cases. Our data confirm the high predictive value of BMD for the mechanical competence of cancellous bone of the intertrochanteric region. However, quantification of cancellous bone structure by image analysis of CT scans may provide additional qualitative information for the analysis of bone strength.

Aged↗

PubMed1999

Comparative evaluation of two density gradient preparations for sperm separation for medically assisted conception.

To evaluate and optimize the sperm separation efficiency of a novel silane-coated silica bead (Puresperm), serial studies were carried out to compare the various sperm parameters between: (i) three-layer (90%-70%-40%) Puresperm and three-layer (90%-70%-40%) conventional polyvinylpyrrolidone (PVP)-coated silica bead (Percoll) gradients; (ii) three-layer (90%-70%-40%) and two-layer (90%-45%) Puresperm gradients and separately the same for Percoll; and (iii) large (3.0 ml) and small (0.75 ml) semen loading volumes on three-layer Puresperm gradients. Normozoospermic semen samples were treated and analysed in 12 replicates for each experiment. Manual evaluation of concentration, percentage motility, percentage vitality, percentage normal morphology; computer-assisted semen analysis evaluation of concentration, percentage motility, grade of motility, motion characteristics (curvilinear velocity, linearity, amplitude of lateral head velocity, beat cross frequency, percentage hyperactivation); and yields from the initial semen samples were compared. Percoll was found to be superior to Puresperm in concentration, percentage motility, percentage vitality and yields after three-layer density gradient centrifugation. There were no significant differences in sperm parameters between two- and three-layer Percoll gradients, but three-layer Puresperm gradients behaved significantly better than two-layer gradients. Large semen volume loads on three-layer Puresperm gradients resulted in greater sperm concentrations, percentage motility, percentage vitality and percentage normal morphology, but small semen volume loads produced greater yields of good-quality spermatozoa. In the light of Percoll being withdrawn from the shelf for the use of assisted reproduction because of the presence of PVP, three-layer Puresperm gradients with large semen loading volumes appear to be an attractive alternative for sperm separation in medically assisted conception.

Adult↗

PubMed1993

[Postmortem high-resolution computed tomography of the lung. Radiologic-morphologic correlations].

To establish precise correlations between high-resolution computed tomography (CT) and normal pulmonary anatomy and pulmonary pathology, 49 lungs affected by different diseases were analysed. Post-mortem high-resolution CT scans were compared with the corresponding macroscopic and microscopic pathological findings. For scanning, lungs were inflated and fixed, which avoided any decrease in the structural resolution of pulmonary parenchyma and allowed a topographically exact correlation between CT appearances and morphological changes. After demonstration of the structural details relevant for CT in normal pulmonary parenchyma, an attempt is made to establish the morphological basis of the following CT phenomena: thickening of interlobular septae, increase in pulmonary translucency, consolidation of the non-nodular alveolar and of the nodular type, and changes in the pleural region. Although CT findings in pulmonary lesions are mainly non-specific, knowledge of the corresponding morphological basis is helpful in diagnostic evaluation.

Animals↗

PubMed1992

The source of protein in the aqueous humor of the normal monkey eye.

In vivo aqueous fluorophotometry, morphology, and computational modeling were combined to examine the source of protein and the pathway by which protein enters the aqueous humor of monkeys. A computational model was developed to determine the likelihood of a diffusional route for delivering plasma proteins from ciliary body capillaries via the iris to anterior chamber aqueous humor, bypassing the posterior chamber. Model predictions were compared to aqueous fluorophotometric data obtained from monkeys following a single intravenous injection of fluoresceinated horseradish peroxidase (F-HRP, 250 mg/kg body mass). Model predictions of the magnitude and time course of anterior chamber F-HRP concentration agree with the fluorophotometric measurements. For example, of anterior chamber F-HRP concentration as a percentage of initial plasma F-HRP concentration at 90 min and 180 min post-injection was predicted to be 0.02% and 0.05%, respectively, and was measured to be 0.01-0.03% and 0.03-0.06%, respectively. In addition, model predictions in the case of a constant plasma protein level also are consistent with experimental data. The steady-state anterior chamber total protein concentration as a percentage of plasma protein concentration was predicted to be 0.2% and was assayed to be 0.05-0.2%. As in our previous study of the normal rabbit eye, morphologic and tracer localization evidence combined with the good agreement between model predictions and experimental data lead to the conclusion that a significant amount of the plasma protein normally present in monkey aqueous humor originates in ciliary body capillaries and diffuses anteriorly through the iris and into the anterior chamber.

Animals↗

PubMed2005

Issues in drug delivery: concepts and practice.

Understanding the transport and deposition of inhaled aerosols is of fundamental importance to inhalation therapy. Herein we address issues that affect drug delivery from experimental and theoretical perspectives. Accordingly, we shall limit our comments to a focused review of laboratory work (ie, an in vitro perspective) and the development of a computer-based 3-dimensional (3D) oral morphology with related computational fluid dynamics (CFD) and particle deposition studies (ie, an "in silico" perspective). To describe the oral region, morphometric data from the literature were employed. With Maya Unlimited, a third-party animation software package, coronal images were used to create initial spline curves, which served as the foundation of a nonuniform rational B-spline surface, representing a 3D morphology. To the best of our knowledge, this study is the first medical application of Maya Unlimited. We have demonstrated that the code can be employed to construct 3D biological structures and perform 3D CFD simulations of aerosols from dry powder inhalers and metered-dose inhalers. A study was also conducted using Fluent, a commercially available software package that has been used extensively in our laboratory for 3D CFD computations. The Maya Unlimited software can generate physiologically realistic oral structures; it has great potential for use in the medical arena, because it requires neither advance technical training nor substantial peripheral ( eg, hardware) support, it allows for the introduction of medical devices ( eg, dry powder inhalers) into simulations, and it predicts 3D CFDpatterns consistent with experimental observations and results of more rigorous software ( Fluent). In the in vitro perspective we considered numerous salient topics, including the performances of dry powder inhalers and metered-dose inhalers, their respective operating characteristics, and relevance to in vivo data. We advocate that 3D CFD software be employed in a complementary manner, in real time, with aerosol therapy protocols in the medical arena, to promote the targeted delivery of inhaled drugs and thereby enhance their efficacies.

Administration, Inhalation↗

PubMed1992

Cytomorphometric analysis of small cell neoplasms of the lung from specimens obtained via bronchoscopy.

Primary neoplasms of the lung composed of small cells consist of undifferentiated small cell carcinoma (UCS), carcinoid tumors (CT) and some non-small cell carcinomas (NonSC) that lack cytoplasmic differentiation. The cytologic identification of tumors from specimens obtained via bronchoscopy sometimes presents difficulties due to overlapping patterns. In order to define additional differentiating criteria, we evaluated Papanicolaou-stained smears from 30 histologically proven cases, 10 from each of the three groups, with statistical analysis of computer-assisted morphologic measures. We identified significant differences between NonSC versus USC and NonSC versus CT with regard to nuclear and cytoplasmic dimensions (P less than .0001) but not between USC and CT. The nuclear:cytoplasmic ratios were similar in all three groups (P = .39). From this preliminary study we conclude that morphometric analysis can distinguish NonSC from USC and CT but not USC from CT.

Biopsy↗

PubMed2001

[Current overview of structural magnetic resonance imaging in schizophrenia].

Non-invasive morphologic imaging (computer tomography, magnetic resonance imaging, MRT) has contributed significantly to our understanding of schizophrenic disorders as diseases of the brain. Improved MRT techniques enable us to analyse anatomical substructures. The present overview evaluates peer-reviewed MRT studies published between 1994 and July 2000 and provides a comparison with our own results. Chronic schizophrenic patients most frequently show an enlargement in the ventricular system along with a reduction in grey matter. A more detailed subdivision into cortical and subcortical regions additionally shows the noted volume reduction to be limited to specific areas within the brain rather than being distributed equally throughout the brain. Within the area of the temporal lobes the two most frequently affected areas are the hippocampus and the gyrus temporalis superior. Alterations within these areas correlate with clinical symptoms such as hallucinations or thought disorders. Within the frontal cortex nearly 70% of all studies show a decrease in overall volume, while 63% note a reduction in size within the thalamus and 60% in the cerebellum. Morphologically speaking these structures therefore play the greatest role in the pathophysiology of schizophrenia and the onset of clinical symptoms. More recent studies also showed a specific progression in subgroups of patients pointing toward a neurodegenerative process. Additionally there are a number of differential antipsychotic effects following longterm treatment with typical neuroleptics as compared to atypical antipsychotics. Based on these findings future longitudinal studies should examine to what extent such a progressive decrease in volume might be influenced by treatment with modern antipsychotics.

Humans↗

PubMed1981

Subclinical changes in brain morphology following cardiac operations as reflected by computed tomographic scans of the brain.

Effects of cardiopulmonary bypass (CPB) and hypothermic circulatory arrest on brain morphology were evaluated by computed tomography (CT). Of 57 children undergoing cardiac operations, 45 (4.5 +/- 2.8 years of age) were operated upon with the use of CPB with high-flow, mildly hypothermic perfusions. Twenty-seven of them were perfused with bubble oxygenators and 18 with membrane oxygenators. In the bubble oxygenator group, all 14 with 20 mu filters in the arterial line showed no postoperative CT changes, whereas four of 13 (31%) with 40 mu filters or without filters showed decreases in brain mass on CT scans. Three of these four patients underwent perfusion for more than 80 minutes. There were no CT changes in the membrane oxygenator group. Twelve infants (10.4 +/- 4.5 months of age) were operated upon with the aid of deep hypothermia and circulatory arrest (core temperature below 20 degrees C). Ten of 12 who had circulatory arrest for less than 60 minutes showed no CT changes, but two infants who had circulatory arrest for more than 60 minutes showed changes similar to those described above. All six children with CT changes had no clinical manifestation of the brain damage, and their CT abnormalities recovered within 6 to 11 months after operation. The specific cause of these changes remains undetermined, but microemboli or hypoxia during operation could be implicated.

Brain Diseases↗

PubMed1997

3D computer-aided reconstruction of the morphology of teeth with malformations.

Malformations of the teeth is a restraining reason for endodontic therapies because of the difficulties they appear during such procedures. These difficulties refer to the knowledge of their internal morphology. The purpose of this study was the 3D reconstruction of two types of malformations of the teeth named "double" teeth and "odontomas". Two "double" teeth and two "odontomas" were studied. All the teeth structures were embedded in polyester resin and from each specimen serial cross sections were taken by using a special microtome. The serial cross sections were photographed under a stereoscopic microscope and digitized. The contours of the external and internal surface of the sections were taken and semiautomatic alignment was achieved. 3D surface representation was used in this project to reconstruct the inner and outer surface of the structures. The results showed in detail the internal structure of the teeth under investigation. The fact that we are able to view and study these teeth from different view points is one of the main advantages of the established method as one could have an idea of the internal structure of these teeth in the space, which is very useful for a clinician. In conclusion, the 3D reconstructing method is a useful tool for the external and internal study of the structure of the teeth with dental anomalies.

Adolescent↗

PubMed2004

Lift-up laminoplasty for myelopathy caused by ossification of the posterior longitudinal ligament of the cervical spine.

BACKGROUND AND AIMS: We have utilized lift-up laminoplasty to treat patients with myelopathy caused by ossification of the posterior longitudinal ligament (OPLL) of the cervical spine. The preliminary surgical outcome with computer-assisted morphological assessment is presented. MATERIAL AND METHODS: The surgical technique of lift-up laminoplasty includes standard posterior exposure of the cervical spine, en-bloc laminectomy, and expansion of the cervical canal by lift-up of the laminae with custom-designed hydroxyapatite laminar spacers and stabilization of the laminae using titanium miniplates. From 1998 to 2003, 10 consecutive patients with cervical myelopathy secondary to OPLL have been treated with this method and comprehensively evaluated. Care was taken to tailor the treatment to individual patients by using different sizes of spacers to adjust the degree of expansion depending on the amount of stenosis of the cervical spine. The degree of expansion of the cervical canal was altered by design, based on the preoperative imaging simulation. RESULTS: Preliminary surgical outcome, evaluated at 6 months after surgery, revealed a significant improvement of neurological function. Image analysis revealed that the cervical canals were significantly expanded, with a mean reduction of 13.1% in the stenosis ratio. Lift-up laminoplasty was effective in the treatment of patients with myelopathy secondary to cervical OPLL, and the amount of expansion could be individually adjusted at the discretion of the surgeon. CONCLUSION: Although analysis with a larger population and a longer follow-up period needs to be undertaken, our method of lift-up laminoplasty appears to be a viable choice among standard posterior cervical approaches for cervical OPLL.

Aged↗