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Biomedical subjects

E Berry

Publications and source records attributed to E Berry.

At least 19 recordsLinked to original sources
PubMed2006

The effect of experience on detectability in local area anatomical noise.

The aim of this study was to investigate if the ability to detect clinically relevant signals, within local area clinically relevant texture, is related to experience. A two alternative forced choice interleaved staircase experiment was conducted on 101 observers split into three groups; group 1 with diagnostic experience, group 2 with experience of imaging but not of making a diagnosis and group 3 with no experience of imaging. Thresholds of detection within synthesized, clinically representative textures were measured for a 15 mm simulated lesion within an MR T1 weighted brain texture and a 2.5 mm diameter simulated lesion embedded within X-ray trabecular bone texture. The results showed that there was a significant difference in threshold detectability between the groups for the brain texture at the 95% significance level but not for the bone texture. The experienced group did not demonstrate a correlation between their bone and brain results. However, the inexperienced group had a significant correlation between the bone and brain results. There was a significant correlation between increasing experience and detectability but this was dependent on the composition of the local area anatomical noise.

Adult↗
PubMed2006

Non-invasive imaging compared with intra-arterial angiography in the diagnosis of symptomatic carotid stenosis: a meta-analysis.

BACKGROUND: Accurate carotid imaging is important for effective secondary stroke prevention. Non-invasive imaging, now widely available, is replacing intra-arterial angiography for carotid stenosis, but the accuracy remains uncertain despite an extensive literature. We systematically reviewed the accuracy of non-invasive imaging compared with intra-arterial angiography for diagnosing carotid stenosis in patients with carotid territory ischaemic symptoms. METHODS: We searched for articles published between 1980 and April 2004; included studies comparing non-invasive imaging with intra-arterial angiography that met Standards for Reporting of Diagnostic Accuracy (STARD) criteria; extracted data to calculate sensitivity and specificity of non-invasive imaging, to test for heterogeneity and to perform sensitivity analyses; and categorised percent stenosis by the North American Symptomatic Carotid Endarterectomy Trial (NASCET) method. RESULTS: In 41 included studies (2541 patients, 4876 arteries), contrast-enhanced MR angiography was more sensitive (0.94, 95% CI 0.88-0.97) and specific (0.93, 95% CI 0.89-0.96) for 70-99% stenosis than Doppler ultrasound, MR angiography, and CT angiography (sensitivities 0.89, 0.88, 0.76; specificities 0.84, 0.84, 0.94, respectively). Data for 50-69% stenoses and combinations of non-invasive tests were sparse and unreliable. There was heterogeneity between studies and evidence of publication bias. INTERPRETATION: Non-invasive tests, used cautiously, could replace intra-arterial carotid angiography for 70-99% stenosis. However, more data are required to determine their accuracy, especially at 50-69% stenoses where the balance of risk and benefit for carotid endarterectomy is particularly narrow, and to explore and overcome heterogeneity. Methodology for evaluating imaging tests should be improved; blinded, prospective studies in clinically relevant patients are essential basic characteristics.

Adult↗
PubMed2006

ESPEN Guidelines on Enteral Nutrition: Geriatrics.

Nutritional intake is often compromised in elderly, multimorbid patients. Enteral nutrition (EN) by means of oral nutritional supplements (ONS) and tube feeding (TF) offers the possibility to increase or to insure nutrient intake in case of insufficient oral food intake. The present guideline is intended to give evidence-based recommendations for the use of ONS and TF in geriatric patients. It was developed by an interdisciplinary expert group in accordance with officially accepted standards and is based on all relevant publications since 1985. The guideline was discussed and accepted in a consensus conference. EN by means of ONS is recommended for geriatric patients at nutritional risk, in case of multimorbidity and frailty, and following orthopaedic-surgical procedures. In elderly people at risk of undernutrition ONS improve nutritional status and reduce mortality. After orthopaedic-surgery ONS reduce unfavourable outcome. TF is clearly indicated in patients with neurologic dysphagia. In contrast, TF is not indicated in final disease states, including final dementia, and in order to facilitate patient care. Altogether, it is strongly recommended not to wait until severe undernutrition has developed, but to start EN therapy early, as soon as a nutritional risk becomes apparent.

Aged↗
PubMed2006

Accurate, practical and cost-effective assessment of carotid stenosis in the UK.

OBJECTIVES: To determine whether less invasive imaging tests [ultrasound (US), magnetic resonance angiography (MRA), computed tomographic angiography (CTA) and contrast-enhanced MRA (CEMRA)], alone or combined, could replace intra-arterial angiography (IAA), what effect this would have on strokes and deaths, endarterectomies performed and costs, and whether less invasive tests were cost-effective. DATA SOURCES: Electronic databases covering the years 1980-2003 inclusive, updated to April 2004. Key journals from 1990 to the end of 2002. REVIEW METHODS: The authors constituted a panel of experts in stroke, imaging, vascular surgery, statistics and health economic modelling. The accuracy of less invasive carotid imaging was systematically reviewed using Standards for Reporting of Diagnostic Accuracy (STARD) methodology, supplemented by individual patient data from UK primary research and audit studies. A systematic review of the costs of less invasive tests, outpatient clinics, endarterectomy and stroke was performed, along with a microcosting exercise. A model of the process of care following a transient ischaemic attack (TIA)/minor stroke was developed, populated with data from stroke epidemiology studies in the UK, effects of medical and surgical interventions, outcomes, quality of life and costs. A survey of UK stroke prevention clinics provided typical timings. Twenty-two different carotid imaging strategies were evaluated for short- and long-term outcomes, quality-adjusted life-years (QALYs) and net benefit. RESULTS: In 41 included studies (2404 patients, median age 60-65 years), most data were available on 70-99% stenosis. CEMRA was the most accurate [sensitivity 0.94, 95% confidence interval (CI) 0.88 to 0.97; specificity 0.93, 95% CI 0.89 to 0.96], compared with US, MRA and CTA, which were all similar (e.g. for US: sensitivity 0.89, 95% CI 0.85 to 0.92; specificity 0.84, 95% CI 0.77 to 0.89). Data for 50-69% stenoses and on combinations of tests were too sparse to be reliable. There was heterogeneity between studies for all imaging modalities except for CTA. The individual patient data (2416 patients) showed that the literature overestimated test accuracy in routine practice and that, in general, tests perform with higher sensitivity and specificity in asymptomatic than in symptomatic arteries. In the cost-effectiveness model, on current UK timings, strategies allowed more patients to reach endarterectomy very quickly, and where those with 50-69% stenosis would be offered surgery in addition to those with 70-99%, prevented most strokes and produced greatest net benefit. This included most strategies with US as first or repeat test, and not those with IAA. However, the model was sensitive to less invasive test accuracy, cost and timing of endarterectomy. In patients investigated late after TIA, test accuracy is crucial and CEMRA should be used before surgery. CONCLUSIONS: In the UK, less invasive tests can be used in place of IAA if radiologists trained in carotid imaging are available. Imaging should be carefully audited. Stroke prevention clinics should reduce waiting times at all stages to improve speed of access to endarterectomy. In patients presenting late after TIA, test accuracy is very important and US results should be confirmed by CEMRA, as patients with 50-69% stenosis are less likely to benefit. More data are required to define the accuracy of the less invasive tests, with improvements made in the data collection methods used and how data are presented. Consideration should also be given to the use of new technologies and randomised trials.

Angiography↗
PubMed2005

The analysis of human cortical bone by terahertz time-domain spectroscopy.

Samples of cortical bone, derived from human femur, have been studied using terahertz time-domain transmission spectroscopy. The relationship between the broadband THz parameters and the previously acquired values of Young's modulus and x-ray attenuation (CT number), and the density of each bone sample, is investigated. The only significant correlation is that between THz transmission and sample density, suggesting that the potential use of THz radiation as a non-invasive probe of bone quality is limited. The spectra of absorption coefficient and refractive index are plotted over the frequency range 0.1-1.25 THz. There is evidence that the sample hydration state is a factor in the resultant THz parameters.

Bone Density↗
PubMed2005

Personalised image-based templates for intra-operative guidance.

The high rate of unplanned perforation, poor fixation, and nerve injury with freehand pedicle screw insertion has led to the use of image-guided navigation systems. Although these improve accuracy, they have several drawbacks that could be overcome by using image-based drilling guide templates. The accuracy of such templates was tested in a cadaveric study of screw placement in the lumbar, thoracic, and cervical regions of the spine. The dimensional stability with autoclaving of duraform polyamide, to be used for manufacturing the guides, was first determined using test specimens. Computed tomography (CT) images were acquired of 4 cadaveric spines, and placement of 4 cervical, 32 thoracic, and 14 lumbar screws was planned. Eighteen personalized drilling guide templates, in four different designs, were built. Orthopaedic surgeons experienced in the freehand techniques used the templates. CT images were acquired to assess placement position with respect to the pedicle. Duraform polyamide was found to be unaffected by sterilization. Two of the template designs facilitated the placement of 20/20 screws without error. Templates can lead to successful screw placement, even in small pedicles, providing their design is optimized for the application area, e.g. with enhanced rotational stabilization.

Bone Screws↗
PubMed2003

The longitudinal Young's modulus of cortical bone in the midshaft of human femur and its correlation with CT scanning data.

This study was concerned with establishing the regional variations in the magnitude of the longitudinal Young's modulus of the cortical bone in the femoral midshaft and with investigating whether a relationship existed between the Young's modulus of bone and the CT number. Were such a relationship to exist this would provide a noninvasive method of assessing the quality of bone in the regions of fixation of implants to bone. The data would be of considerable aid to designers of implant stems to withstand the stresses arising at its interface with the bone. Five pairs of fresh frozen human femora were used. Several beam-shaped small specimens were methodically harvested from each pair and were used to measure the longitudinal modulus adopting the three-point bending test, which was carried out with a specially constructed and validated apparatus. CT scans of the bone were obtained, prior to harvesting the specimens, and the CT number was measured at locations corresponding with the specimen sites. The results indicate that in the femoral midshaft the cortical bone has an average Young's modulus value of 18600 +/- 1900 MPa. This agrees well with data obtained by other researchers using different experimental methods. Statistical analyses revealed no regional variations in the value of the longitudinal modulus of the bone. No correlation was found between the bone modulus and the CT number. Thus a noninvasive method for establishing the bone properties still remains a challenge.

Aged↗
PubMed2003

Quality assessment of the cortical bone of the human mandible.

This study is the first to investigate simultaneously both the regional and the directional variations in mechanical properties and computed tomography (CT) numbers of the fresh mandible bone and to explore the correlation between the two sets of data with a view to provide a noninvasive method for determining the bone quality for designers of dental implants. Using a three-point bending test the regional variation of Young's modulus of bone in the human mandible was determined from five fresh specimens from donors representative of patients in need of dental implants in that some of the mandibles were fully dentulate, some partly so, and some fully edentulate. While a pattern of the modulus distribution was evident in the mandibles we tested, these mandibles did have, as a result of their respective states, their own peculiarities. We determined also the directional variations of the modulus for the mandible, which are due to the anisotropic nature of bone. The modulus values obtained in our study were much lower than those listed in the only other published study, which was conducted on dry mandibles. These differences in the modulus data from the two studies were attributed partly to the differences in condition of the bone and differences in the dimensions of specimens tested in the two studies. Because the values of the modulus obtained in this study are lower than those previously published, they would be safer as a basis for implant designs. A weak correlation was found between the modulus values and the CT number of the mandible. This would not be sufficient for accurate predictions of the bone properties from CT scans. The development of a noninvasive method for determining the bone quality in various patients thus remains a challenge for researchers.

Aged↗
PubMed2003

The Karyote physico-chemical genomic, proteomic, metabolic cell modeling system.

Modeling approaches to the dynamics of a living cell are presented that are strongly based on its underlying physical and chemical processes and its hierarchical spatio-temporal organization. Through the inclusion of a broad spectrum of processes and a rigorous analysis of the multiple scale nature of cellular dynamics, we are attempting to advance cell modeling and its applications. The presentation focuses on our cell modeling system, which integrates data archiving and quantitative physico-chemical modeling and information theory to provide a seamless approach to the modeling/data analysis endeavor. Thereby the rapidly growing mess of genomic, proteomic, metabolic, and cell physiological data can be automatically used to develop and calibrate a predictive cell model. The discussion focuses on the Karyote cell modeling system and an introduction to the CellX and VirusX models. The Karyote software system integrates three elements: (1) a model-building and data archiving module that allows one to define a cell type to be modeled through its reaction network, structure, and transport processes as well as to choose the surrounding medium and other parameters of the phenomenon to be modeled; (2) a genomic, proteomic, metabolic cell simulator that solves the equations of metabolic reaction, transcription/translation polymerization and the exchange of molecules between parts of the cell and with the surrounding medium; and (3) an information theory module (ITM) that automates model calibration and development, and integrates a variety of data types with the cell dynamic computations. In Karyote, reactions may be fast (equilibrated) or slow (finite rate), and the special effects of enzymes and other minority species yielding steady-state cycles of arbitrary complexities are accounted for. These features of the dynamics are handled via rigorous multiple scale analysis. A user interface allows for an automated generation and solution of the equations of multiple timescale, compartmented dynamics. Karyote is based on a fixed intracellular structure. However, cell response to changes in the host medium, damage, development or transformation to abnormality can involve dramatic changes in intracellular structure. As this changes the nature of the cellular dynamics, a new model, CellX, is being developed based on the spatial distribution of concentration and other variables. This allows CellX to capture the self-organizing character of cellular behavior. The self-assembly of organelles, viruses, and other subcellular bodies is being addressed in a second new model, VirusX, that integrates molecular mechanics and continuum theory. VirusX is designed to study the influence of a host medium on viral self-assembly, structural stability, infection of a single cell, and transmission of disease.

Animals↗
PubMed2002

Evaluation of image quality in terahertz pulsed imaging using test objects.

As with other imaging modalities, the performance of terahertz (THz) imaging systems is limited by factors of spatial resolution, contrast and noise. The purpose of this paper is to introduce test objects and image analysis methods to evaluate and compare THz image quality in a quantitative and objective way, so that alternative terahertz imaging system configurations and acquisition techniques can be compared, and the range of image parameters can be assessed. Two test objects were designed and manufactured, one to determine the modulation transfer functions (MTF) and the other to derive image signal to noise ratio (SNR) at a range of contrasts. As expected the higher THz frequencies had larger MTFs, and better spatial resolution as determined by the spatial frequency at which the MTF dropped below the 20% threshold. Image SNR was compared for time domain and frequency domain image parameters and time delay based images consistently demonstrated higher SNR than intensity based parameters such as relative transmittance because the latter are more strongly affected by the sources of noise in the THz system such as laser fluctuations and detector shot noise.

Diagnostic Imaging↗
PubMed2002

Wavelet compression in medical terahertz pulsed imaging.

This paper concerns the robustness of discrete wavelet transform (DWT) compression in terahertz pulsed imaging (TPI). TPI datasets consist of terahertz time-domain series which are sampled at each 'pixel' of the image, leading to file sizes which are typically of the order of several megabytes (MB) per image. This makes efficient compression highly desirable for both transmission and storage. However, since the data may be required for diagnostic purposes it is essential that no relevant information is lost or artefacts introduced. We show that for a nylon step wedge the estimates of refractive index and absorption coefficients are not significantly altered when the terahertz data are reconstructed from only 20% of DWT coefficients.

Algorithms↗
PubMed2002

An introduction to medical imaging with coherent terahertz frequency radiation.

Methods have recently been developed that make use of electromagnetic radiation at terahertz (THz) frequencies, the region of the spectrum between millimetre wavelengths and the infrared, for imaging purposes. Radiation at these wavelengths is non-ionizing and subject to far less Rayleigh scatter than visible or infrared wavelengths, making it suitable for medical applications. This paper introduces THz pulsed imaging and discusses its potential for in vivo medical applications in comparison with existing modalities.

Alginates↗
PubMed2002

Wheat grass juice in the treatment of active distal ulcerative colitis: a randomized double-blind placebo-controlled trial.

BACKGROUND: The use of wheat grass (Triticum aestivum) juice for treatment of various gastrointestinal and other conditions had been suggested by its proponents for more than 30 years, but was never clinically assessed in a controlled trial. A preliminary unpublished pilot study suggested efficacy of wheat grass juice in the treatment of ulcerative colitis (UC). METHODS: A randomized, double-blind, placebo-controlled study. One gastroenterology unit in a tertiary hospital and three study coordinating centers in three major cities in Israel. Twenty-three patients diagnosed clinically and sigmoidoscopically with active distal UC were randomly allocated to receive either 100 cc of wheat grass juice, or a matching placebo, daily for 1 month. Efficacy of treatment was assessed by a 4-fold disease activity index that included rectal bleeding and number of bowel movements as determined from patient diary records, a sigmoidoscopic evaluation, and global assessment by a physician. RESULTS: Twenty-one patients completed the study, and full information was available on 19 of them. Treatment with wheat grass juice was associated with significant reductions in the overall disease activity index (P=0.031) and in the severity of rectal bleeding (P = 0.025). No serious side effects were found. Fresh extract of wheat grass demonstrated a prominent tracing in cyclic voltammetry methodology, presumably corresponding to four groups of compounds that exhibit anti-oxidative properties. CONCLUSION: Wheat grass juice appeared effective and safe as a single or adjuvant treatment of active distal UC.

Adult↗
PubMed2002

Flexible tubular replicas of abdominal aortic aneurysms.

The aim of this study was to manufacture life-size, flexible, tubular replicas of human abdominal aortic aneurysms and the associated vasculature, suitable for use in a training simulator for endovascular procedures. Selective laser sintering was used to create a geometrically correct master model for each of ten anatomical variations. The masters were used to generate flexible latex replicas. The use of the replicas in the training simulator was demonstrated. In total ten silicone rubber models were produced. When connected into the training simulator and perfused at arterial pressure it was possible to deploy an endovascular stent under fluoroscopic control and to perform angiography. The study has shown that conventional rapid prototyping technology can be used to manufacture flexible, radiolucent replicas which provide a realistic training environment for endovascular procedures.

Angiography, Digital Subtraction↗
PubMed2002

Recommended micronutrient supplementation for institutionalized elderly.

A committee nominated by the Israel Ministry of Health examined the relevant literature and the local recommendations as well as the recommendations from other countries and suggested a daily micronutrient supplementation for institutionalized elderly living in institutions supervised by the Ministry of Health. The micronutrient preparatory, tailored for this population, is designed to contain about half the RDA for most of the vitamins and some microelements. Biotin and vitamins C, D and B12 as well as zinc, copper, chromium and molybdenum are suggested at a level higher than half the RDA, whereas fluorine, at a lower level. Major elements (calcium, magnesium and phosphorus) are excluded and should be supplied separately. Vitamin K and iron are also excluded. Fat-soluble vitamins should be microencapsulated. Micronutrient supplementation for institutionalized elderly is part of the Ministry of Health s balanced nutrition policy. The committee s recommendations are also applicable to the free-living elderly population.

Journal Article↗
PubMed2001

Laser morphometric analysis of the glenoid fossa of the scapula.

We have assessed the topography of the articular surface of the glenoid fossa using a laser morphometric technique. Eighteen cadaveric scapulae from individuals aged 66 to 90 years were scanned and the degree of version of five lines constructed in the horizontal plane was determined. The lines comprised a transverse reference line (equatorial midline) located midway between the superior and inferior tubercles of the fossa, lines at 45% of the height of the glenoid fossa above and below the equatorial line, and further lines midway between these pairs. The cartilage-covered glenoid articular surface displayed differences in version between its superior and inferior aspects; the mean difference in version between the superior and inferior lines was 11.2 degrees, with the most superior line being retroverted 8.2 degrees with respect to the equatorial midline and the most inferior line anteverted 3.2 degrees. These data may be of importance in understanding the kinematics of the glenohumeral joint and in translating this knowledge to joint replacement surgery.

Aged↗