SEARCH · PubMed Health

Results for “computational morphology”

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 55 records · Page 3Linked to original sources

PubMed1986

Hepatic vein occlusion: morphologic features on computed tomography and ultrasonography.

Hepatic vein occlusion causes morphologic changes that can be demonstrated by computed tomography (CT) and ultrasound. In this study the imaging findings of acute, subacute, and chronic occlusion of the hepatic veins were analyzed retrospectively in 9 patients and correlated with the histopathologic changes. The CT findings were focal or scattered hypodense parenchymal lesions of the liver before and a patchy enhancement after intravenous bolus injection of contrast material. In none of the cases could the hepatic veins be identified. Hepatomegaly with relative enlargement of the caudate lobe was almost always observed. Ultrasonography demonstrated solid material within the major hepatic veins, intrahepatic venous collaterals, and focal parenchymal lesions, which varied with the stage of the disease: a hypoechogenic area was observed in acute hepatic vein thrombosis with subsequent hemorrhagic infarction; hyperechogenic lesions corresponded with fibrotic zones in chronic disease. Ascites was shown by both methods in all patients.

Adult↗

PubMed1989

[Orientational analysis of the ultrastructural architecture of the fibrous base of human articular cartilage].

An equivalent well reproduced reliable method of quantitative morphological orientational analysis has been chosen. Determination of the character, predominant direction and degree of orientation of the structural elements have been foreseen. Computer morphological orientational analysis of the fibrous architectonics of the human articular cartilage makes it possible to present a quantitative characteristics of peculiarities in its structural organization along the distance from the articular surface up to the subchondral bone. Certain objective data obtained confirm existance of three layers in the cartilage having various construction of the fibrous base: superficial layer with a predominant orientation of the collagenous fibrils in parallel with the articular surface; central--nonoriented; deep layer--with a radial orientation of fibrils. The method of orientational analysis applied can be used for quantitative characteristic of the fibrous base architectonics of any part of the locomotor apparatus in the human being and animals.

Adult↗

PubMed1998

Noninvasive characterization of plaque morphology using helical computed tomography.

BACKGROUND: Evidence suggests that atherosclerotic plaque composition and morphology are more important predictors of plaque stability and clinical behavior than the degree of vessel stenosis. Unfortunately, noninvasive methods of plaque characterization in situ using duplex ultrasound have been largely unsuccessful. We investigated the accuracy of helical computed tomography (HCT) in defining plaque morphology in patients undergoing carotid endarterectomy. METHODS: Candidates for endarterectomy were enrolled prospectively and underwent HCT with intravenous contrast injection. The attenuation values (in Hounsfield Units) of plaque features such as calcium, fibrous tissue, and lipid were measured and correlated with the tissue types seen on microscopic examination. Percent luminal stenosis derived from transverse HCT images was also compared to values obtained from duplex ultrasound. SETTING: Ambulatory patients referred to a tertiary, metropolitan medical center. RESULTS: A total of 21 out of 22 cases were suitable for comparison. Qualitatively, HCT accurately defined plaque features containing calcium, fibrous stroma, and lipid. Using tissue attenuation values (Hounsfield Units - H), HCT distinguished between lipid and fibrous stroma (means 39+/-12 H and 90+/-24 H, respectively, p<0.001). HCT-derived calculations of percent stenosis also correlated with the ultrasound data (p<0.001). CONCLUSIONS: HCT is an accurate, noninvasive means for studying detailed plaque morphology and composition. This technique provides the basis for further studies correlating plaque anatomy with clinical behavior.

Aged↗

PubMed2001

Measurement on Tinetti test: instrumentation and procedures.

A measurement system and associate signal processing procedures for quantifying subject's performance during the performance-oriented assessment of balance as defined in Tinetti test (TT) is described. It is based on two inclinometers measuring trunk inclination in two orthogonal planes. Signals from the transducers are acquired by a PC through A/DC board. Signal processing consists in computing morphological parameters describing the main features of subject movement during the different TT maneuvers. The system is simple, cheap, user friendly, causes no discomfort to the patient and can easily be modified to comply with either new requirements or the needs of other performance tests dealing with trunk movement. Preliminary results of measurements on both normals and patients suggest the viability of this approach and the possibility of discriminating normal from abnormal performance, based on the values of the morphological parameters.

Aged↗

PubMed1997

Cryptogenic fibrosing alveolitis and the fibrosing alveolitis of systemic sclerosis: morphological differences on computed tomographic scans.

BACKGROUND: The purpose of this study was to identify morphological differences on the computed tomographic (CT) scan between cryptogenic fibrosing alveolitis (CFA) and the fibrosing alveolitis associated with systemic sclerosis (FASSc), and to examine their biological relevance. METHODS: One hundred and seven patients with CFA (n = 55) or FASSc (n = 52) who had undergone thin section CT scanning were included. Multivariate analysis was used to identify morphological differences on the CT scans between lone CFA and FASSc, and to determine whether the pattern and distribution of disease on the CT scans were functionally significant (as judged by the lung transfer factor (TLCO), forced vital capacity (FVC), and arterial oxygen tension (PaO2)) or predictive of survival (independent of the type and extent of fibrosing alveolitis, age, sex, and smoking history). RESULTS: Increasingly extensive disease on CT scans was associated with a coarser reticular pattern (increase in reticular score per percentage increase in disease extent = 0.06, 95% confidence interval (CI) 0.03 to 0.09, p < 0.0005) and increasing upper zone involvement (increase in ratio of upper zone to total disease per percentage increase in disease extent = 0.002, 95% CI 0.000 to 0.003, p < 0.04). Patients with CFA were characterised by a higher upper zone ratio (difference = 0.08, 95% CI 0.02 to 0.13, p < 0.004) and a weak trend towards a coarser reticular pattern (p = 0.09), independent of disease extent. Smokers with CFA had more upper zone involvement (difference = 0.11, 95% CI 0.05 to 0.16, p < 0.0005) and a coarser reticular pattern (difference in reticular score = 1.92, 95% CI 0.27 to 3.55, p < 0.02) than smokers with FASSc. The extent of disease on the CT scan was predictive of lung function impairment and survival but the pattern and distribution of disease were not. CONCLUSIONS: Patients with CFA have relatively more upper zone involvement than those with FASSc independent of the extent of disease on the CT scan. This finding may result from smoking related damage but is not functionally significant.

Diagnosis, Differential↗

PubMed1997

Relationships between the orientation and moment arms of the human jaw muscles and normal craniofacial morphology.

It has been suggested that subjects with increased vertical craniofacial dimensions have relatively oblique orientated jaw muscles with a reduced possibility to restrain the vertical component of craniofacial growth. To test this hypothesis, relationships were investigated between the spatial orientation of the jaw muscles and the craniofacial morphology. Computer reconstructions of the external shape of the jaw muscles of 30 adult males with a normal skull were made with the use of serial magnetic resonance imaging (MRI) scans. The orientation of the jaw muscles was defined by a regression line through the centroids of the serial cross-sections. Sagittal and frontal projections of the moment arms of the muscles were measured with respect to the centre of the ipsilateral condyle. Craniofacial morphology was analysed three-dimensionally using lateral head films and coronal MRI scans. The cephalometric data were analysed statistically using regression and factor analyses. Six cephalometric factors with Eigen values higher than 1 were correlated with jaw muscle orientation and moment arm data, using a multiple regression analysis. The anterior face height factor was significantly correlated with the orientation of the jaw opening muscles in the sagittal plane but was not significantly correlated with the orientation of the mandibular elevators. The sagittal moment arms of the mandibular elevators showed significant correlations with the factors describing the gonial angle and the posterior face height. It was concluded that the variation of spatial orientation of the human jaw closing muscles is predominantly associated with the variation of mandibular morphology (expressed by the gonial angle) and the posterior face height. The orientation of the jaw opening muscles shows significant relationships with anterior vertical craniofacial dimensions. The hypothesis that persons with an increased anterior face height have relatively oblique orientated jaw elevators was rejected.

Adult↗

PubMed2004

The role of load-carrying in the evolution of modern body proportions.

The first unquestionably bipedal early human ancestors, the species Australopithecus afarensis, were markedly different to ourselves in body proportions, having a long trunk and short legs. Some have argued that 'chimpanzee-like' features such as these suggest a 'bent-hip, bent-knee' (BHBK) posture would have been adopted during gait. Computer modelling studies, however, indicate that this early human ancestor could have walked in a reasonably efficient upright posture, whereas BHBK posture would have nearly doubled the mechanical energy cost of locomotion, as it does the physiological cost of locomotion in ourselves. More modern body proportions first appear at around 1.8-1.5 Ma, with Homo ergaster (early African Homo erectus), represented by the Nariokotome skeleton KNM-WT 15000, in which the legs were considerably longer in relation to the trunk than they are in human adults, although this skeleton represents an adolescent. Several authors have suggested that this morphology would have allowed faster, more endurant walking. But during the same period, the archaeological record indicates a sharp rise in distances over which stone tools or raw materials are transported. Is this coincidental, or can load-carrying also be implicated in selection for a more modern morphology? Computer simulations of loaded walking, verified against kinetic data for humans, show that BHBK gait is even more ineffective while load-carrying. However, walking erect, the Nariokotome individual could have carried loads of 10-15% body mass for less cost, relative to body size, than AL 288-1 walking erect but unloaded. In fact, to the extent that our sample of humans is typical, KNM-WT 15000 would have had better mechanical effectiveness in bearing light loads on the back than modern human adults. Thus, selection for effectiveness in load-carrying, as well as in endurant walking, is indeed likely to have been implicated in the evolution of modern body proportions.

Animals↗

PubMed1999

Effects of neonatal attenuation of axoplasmic flow or transection of the rat's infraorbital nerve on the morphology of individual trigeminal primary afferent terminals in the brainstem.

Attenuation of axoplasmic transport in the infraorbital nerve (ION), or transection of this trigeminal (V) branch at birth, results in degradation of the central cellular aggregates related to the mystacial vibrissae. However, blockade of axoplasmic transport does not result in the nearly 90% loss of ION ganglion cells that follows neonatal transection of this nerve. The present study was undertaken to further characterize the response of individual ION axons to attenuation of axoplasmic transport and to compare these effects to the changes observed following nerve transection. Neurobiotin injections were made into the V ganglion on postnatal day (P-) 6 in normal rats and animals that had vinblastine applied to the ION or received transection of the ION on P-0. Individual labeled fibers in the portions of V nucleus principalis (PrV) and subnucleus interpolaris (SpI) innervated by the ION were drawn from single sections with the aid of a computer. Morphological analysis of fibers drawn in SpI indicated no significant differences between axons from normal and vinblastine-treated animals. The fibers drawn from rats that sustained ION transection had significantly more branch points (P < 0.05) than those from either normal or vinblastine-treated animals. In PrV, fibers drawn from vinblastine-treated rats had a slightly, but significantly, larger total process length and cross-sectional area than those from the normal animals (P < 0.05). There were no other significant differences among the three groups of axons. These results support the conclusion that application of vinblastine to the developing ION does not dramatically alter the morphologic patterning of the central arbors of its axons.

Afferent Pathways↗

PubMed1987

[Computerized tomography image of chronic urogenital bilharziasis in childhood and adolescence].

With the help of 9 cases in childhood the computer-morphologic picture of the urogenital bilharziosis free of overshadowing with the typical cup-shaped calcifications of the walls of the urinary bladder and the rind-shaped calcium deposits of the distal ureters are demonstrated. On account of the increasing exchange of staff and the increasing number of probationers and students from tropical countries also in our country the physician working in the field of urology and radiology will more frequently be confronted with the typical forms of this parasitosis.

Adolescent↗

PubMed2003

Characterization of left atrium and distal pulmonary vein morphology using multidimensional computed tomography.

OBJECTIVES: This study was designed to examine the dimensions and morphology of left atrial (LA) and distal pulmonary veins (PVs) using multidetector helical computed tomography (MDCT). BACKGROUND: Detailed knowledge of LA and PV anatomy will assist in the development of techniques for ablative intervention. Multidetector helical computed tomography is a method for multidimensional imaging of cardiac anatomy. METHODS: Multidetector helical computed tomography was used to image the LA and PVs in 70 subjects with and 47 subjects without atrial fibrillation (AF). Accuracy of the MDCT data was confirmed by correlation with echocardiography and endocardial electrogram recordings. RESULTS: Left atrial and PV dimensions were significantly larger in AF versus non-AF subjects, men versus women, and subjects with persistent versus paroxysmal AF. There were no differences between groups in morphologic detail. CONCLUSIONS: Multidetector helical computed tomography images of the LA and PVs are accurate and provide detailed anatomic information. Significant differences in dimensions but not morphologic detail were apparent between groups.

Adult↗

PubMedDate not supplied

Renal and perirenal space involvement in acute pancreatitis: spiral CT findings.

BACKGROUND: This study was conducted to estimate the prevalence and morphologic computed tomographic (CT) features of renal and perirenal space abnormalities in acute pancreatitis in correlation with the severity of pancreatitis. METHODS: One hundred fifty-nine contrast-enhanced CT scans of 100 consecutive patients with acute pancreatitis were retrospectively and independently reviewed by three observers. All CT images were obtained using contrast-enhanced helical CT (collimation width = 5 mm, table increment = 7 mm/s, reconstruction interval = 5 mm, scan delay time = 30-50 s). Additional maximized images (field of view = 260 mm) of the perirenal space were available for review. All CT scans were scored with the CT Severity Score Index: pancreatitis was graded as mild (0-2 points), moderate (3-6 points), and severe (7-10 points). Interobserver agreement for both the severity score and the presence of renal and perirenal involvement was calculated. Correlation between the prevalence of complications and the degree of pancreatitis was estimated. RESULTS: CT scans were graded as mild (n = 59), moderate (n = 82), and severe (n = 18). Abnormalities detected included perirenal stranding (n = 37 patients, 26 bilateral), perirenal fluid collections (n = 10 patients, one bilateral), ureteral encasement (n = 2 patients), renal vein thrombosis (n = 1 patient), and renal parenchymal abnormalities (n = 1 patient). The interobserver agreement range for scoring the degree of pancreatitis and the overall presence of abnormalities was 75.5-79.2% and 59.8-100%, respectively. Except for stranding of the perirenal fat, no statistically significant differences between the presence of abnormalities and the severity of pancreatitis (moderate or severe) was observed with Fisher's exact test. Also, no preferential left-sided localization of complications was observed. CONCLUSIONS: The incidence of renal and perirenal complications from acute pancreatitis is higher than previously estimated (7%). We found no significant correlation between the prevalence of major complications and the severity of pancreatitis. These findings are important because these complications may have an impact on therapeutic strategy and can affect prognosis.

Acute Disease↗

PubMed2001

Adrenal hemorrhage after orthotopic liver transplantation: MR appearance.

The purpose of this paper is to describe the MR imaging findings of right adrenal hemorrhage after orthotopic liver transplantation. Twenty-seven orthotopic liver transplantation patients underwent MR studies of the liver and/or biliary system. Patients were referred to MR examination because of suspected biliary complications ( n=22) or for evaluation of mass lesions ( n=5). The standard MR protocol included T1-weighted spin-echo (SE) or gradient-recalled echo (GRE) images and T2-weighted turbo SE (TSE) images with fat suppression. In addition, cholangiography pulse sequences and/or contrast-enhanced T1-weighted images were obtained according to specific indications. In 2 patients a right adrenal mass was detected at MR imaging. Three to 4 weeks after transplantation, the lesions were markedly hyperintense on T2-weighted images and showed a hypointense capsule. Follow-up MR examinations revealed a slight decrease in size and a change in morphology. Computed tomography examinations of these 2 patients, obtained 10 weeks after transplantation, showed resolution of the hemorrhage and transformation into a cystic lesion in one case and a complete resolution of the hemorrhage and a normal right adrenal gland in the other case. Adrenal hemorrhage after liver transplantation shows typical MR features and should not be mistaken for an adrenal tumor or a postoperative abscess.

Adrenal Gland Diseases↗

PubMed2005

[Matching of mammary microcalcifications on images from different views].

PURPOSE: In order to increase sensitivity and specificity in the diagnosis of breast cancer, more than one - generally two or three - mammograms of the same breast are obtained. In order to be able to carry out 3D reconstruction of microcalcification clusters on one hand, and efficiently fuse the information they carry on the other hand, one needs to match corresponding regions of microcalcifications from the different views. Unfortunately, this may be difficult at times. To help the situation, we have developed in this paper, a technique to automatically match microcalcifications found on pairs of mammograms from the same breast. MATERIALS AND METHODS: We used the computed morphological characteristics of individual microcalcifications to build a likeness function to match the microcalcifications. The geometrical constraint suitable for the system used was then applied to reduce the possibilities. From the remaining possibilities, the one with the highest likeness was selected as pair of corresponding microcalcifications. RESULTS: This technique was tested on a number of real cases and yielded 77.14% of good matches. CONCLUSION: This technique provides good results and could therefore be used either directly or for 3D-reconstruction of clustered microcalcifications.

Breast Diseases↗

PubMed2003

Magnetic resonance imaging using hyperpolarized 3He-Gas.

RATIONALE AND OBJECTIVES: Current imaging procedures of the lung concentrate on visualization of morphology. Computed tomography is the imaging method of choice for the majority of pulmonary diseases. Functional data are commonly obtained from arterial blood gas analysis, spirometry, and body plethysmography, which all suffer from lack of regional information. MATERIALS AND METHODS: Magnetic resonance imaging (MRI) of the lung has been advanced recently by the use of hyperpolarized 3He as a new contrast mechanism. Four different image acquisition modes are performed during a typical patient study. RESULTS: 3He-MRI yields functional information about the lung with a high spatial and temporal resolution, avoiding the risks of ionizing radiation. The method is currently limited by high costs and restricted availability of the gas. CONCLUSION: In this article, the experience obtained at the University of Mainz, being Europe's most experienced center performing 3He-MRI in humans, is reviewed against the international background.

Contrast Media↗

PubMed2003

The representation of grammatical categories in the brain.

Language relies on the rule-based combination of words with different grammatical properties, such as nouns and verbs. Yet most research on the problem of word retrieval has focused on the production of concrete nouns, leaving open a crucial question: how is knowledge about different grammatical categories represented in the brain, and what components of the language production system make use of it? Drawing on evidence from neuropsychology, electrophysiology and neuroimaging, we argue that information about a word's grammatical category might be represented independently of its meaning at the levels of word form and morphological computation.

Journal Article↗

PubMed2004

Automated morphometric analysis of the cat retinal alpha/Y, beta/X and delta ganglion cells using wavelet statistical moment and clustering algorithms.

Computational morphological analysis comprises the development of measures (indicators) that describe different form attributes of a neuron and provides additional parameters for classification algorithms. Our work addressed the problem of small group sizes often encountered in neuromorphological and neurophysiological research, automated classification tasks (unsupervised learning) and introduced a new morphological measure: the wavelet statistical moment. We analysed cat alpha/Y, beta/X and delta Golgi-stained retinal ganglion cells using six different shape features (circularity, 2(nd) statistical moment and entropy of Gaussian blurred images, wavelet statistical moment, number of terminations and the fractal dimension). This allowed us to compare the sensitivity of the methods in uniquely describing morphological attributes of these cells.

Algorithms↗

PubMed2000

Mithramycin inhibits intimal hyperplasia of vein grafts after transplantation of the jugular vein to the abdomainal aorta in rats.

OBJECTIVE: The intimal hyperplasia caused by mig ration and proliferation of the smooth muscle cells play a most important role in the stenosis of the vein grafts. This study is to explore how the C-myc onc ogene and its protein contribute to the intimal hyperplasia after the jugular ve in is transplanted to the abdominal aorta and to assess the effect of Mithramyci n on the intimal hyperplasia. METHODS: In 60 Wistar rats, a 0.8 cm segment of the right j ugular vein graft was interposed at the level of the abdominal aorta. The experi ment group received Mithramycin (150 mug/kg IP) 1 h before and after the operat ion. The control group received normal saline, specimens of vein graft at 2 and 6 h postoperatively were subjected respectively to in situ hybridization. The ve in grafts 4 weeks after operation were perfusion fixed. The specimens were stain ed with hemotoxylin-eosin and the computer morphologic analysis system was used to evaluate the degree of intimal thickening. Immunohistochemistry studies of m uscle-specific &amg;-actin, C-myc protein and 5'-Bromodeoxyuridine were perfor med. RESULTS: The areas of neointimal and the ratios of neointimal t o medial area were significantly smaller and lower in the Mithramycin-treated t han in the control rats (P<0.05). The 5'-Brdu labeli ng rate between the two groups were also different significantly (P<0.05). Muscl-specific alpha-actin showed that the smooth muscle ce lls formed the most area of myointimal hyperplasia. Steady-state C-myc mRNA le vel was incre ased from 2 h to 6 h postoperatively. The positive rate of the placebo-treated group was higher significantly than that of the Mithramycin-treated group (P<0.05). CONCLUSIONS: Mithramycin may effectively inhibits transcription of C-myc in proliferating vascular smooth muscle cells and could be useful in the prevention of restenosis after vascularization. These results support the hy pothesis that systemic administration of Mithramycin might immediately prevent i ntimal proliferation.

Journal Article↗

PubMed1991

Testing cerebral function: will it help the understanding or diagnosis of central nervous system disease?

The recent introduction of non-invasive tools for the quantitative mapping of cerebral function in humans (e.g. cerebral blood flow measurement and positron emission tomography) in conjunction with detailed in vivo tomographic morphology (computed tomography and magnetic resonance imaging) has led to a fruitful interaction between clinicians and fundamental neuroscientists. This has led to the development of a productive, scientifically sound human neuroscience whose aim is to explore brain function directly in the human subject. With respect to the physiological state, this research has resulted in major findings especially in the fields of visual function, attention, anticipatory anxiety, language, motion and somaesthesia. The study of disease states has resulted in less impressive findings. The investigation of patients with focal brain lesions has revealed time-dependent alterations of cerebral blood flow and energy metabolism in widespread grey matter structures, as a result of disconnection; however, these functional alterations apparently reflect a variety of processes, from Wallerian or retrograde degeneration to reversible or irreversible transsynaptic or transneuronal effects, which makes their interpretation uncertain. Likewise the cellular and neurochemical basis for the recovery of energy metabolism in deafferented brain areas remains speculative. Although several types of metabolic effects due to disconnection are correlated to well-defined neuropsychological/behavioural impairment (and recovery therefrom) unexplained discrepancies exist and their role in individual patients remains obscure. The study of the brain's 'functional reserve' by activation paradigms would presumably shed more light on the clinical/functional brain relationships in disease but such investigations are hampered by unresolved methodological issues such as the choice criteria for the control population (?healthy controls, ?asymptomatic brain-lesioned patients) and task (?pseudo-impaired). There are also complex statistical issues because of the requirement to study single cases as a result of the inter-subject variability in lesion topography, size or duration, as well as in the pattern and degree of behavioural impairment. The design of controlled experimental paradigms in non-human primates, involving controlled lesions and sequential behavioural and PET assessment, may help to resolve some of these issues.

Brain Diseases↗