947 research outputs found
Optimization of Axial Resolution
Abstract: To improve the axial resolution of ultrasonic elastography, by taking the advantage of code excitation and frequency compounding, multi-frequency with coded excitation for elastography (FCCE) was proposed. FCCE adopts the Chirp signal excitation scheme and strikes a balance in the selection of sub-signal bandwidth, the bandwidth overlap and the number of sub-strain image based on theoretical derivation, so as to further improve the axial resolution of elastic image. On MATLAB, multi-frequency with coded excitation for elastography was implemented and compared with short pulse. Experiments have proved that, compared with the short pulse, the elastographic signal-to-noise ratio (SNRe) and contrast-to-noise ratio (CNRe) were improved significantly. Moreover, probing depth, axial resolution and target detection were improved too. Therefore, the FCCE technology can effectively improve the elastography quality and can be applied to ultrasonic clinical trials. Copyright © 2014 IFSA Publishing, S. L
Does Intravenous Infusion Influence Diagnostic UltrasoundâInduced Pulmonary Capillary Hemorrhage?
Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/145537/1/jum14555.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/145537/2/jum14555_am.pd
Myocardial involvement during the early course of type 2 diabetes mellitus: usefulness of Myocardial Performance Index
To evaluate whether myocardial performance index detects a subclinical impairment of left ventricular systolic and diastolic function in patients with early stage of type 2 diabetes, without coronary artery disease, with or without hypertension. Furthermore, to evaluate whether some echocardiographic parameters relate to the metabolic control. Fourty-five consecutive male patients (mean age 52.5 years) with type 2 diabetes mellitus of recent onset (23 hypertensives and 22 normotensives) and 22 age matched healthy controls males were analysed. All participants had normal exercise ECG. All subjects underwent standard and Doppler echocardiography for the assessment of the isovolumic Doppler time interval and Doppler-derived myocardial performance index. In all diabetic patients a glycated haemoglobin test was also performed
Diffusion and applications of musculoskeletal ultrasound in Italian Rheumatology Units
The Musculoskeletal Ultrasound Study Group of the Italian Society of Rheumatology (SIR) was founded during the 68th SIR Congress, on November 2011. The request of activation of this group was based on the increasing interest and the widespread diffusion of ultrasound in the scientific rheumatology community and on the solid experience of some Italian rheumatologists in the field. The aims of the Study Group are to stimulate the applications and use of ultrasound in the clinical practice at the level of the Italian rheumatology units and, in addition, to develop research projects at a national level..
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Summative Clinical Competency Assessment: A Survey of Ultrasound Practitionersâ Views
Clinical competency and the assessment of core skills is a crucial element of any programme leading to an award with a clinical skills component. This has become a more prominent feature of current reports on quality health care provision. This project aimed to determine ultrasound practitionersâ opinions about how best to assess clinical competency. An on-line questionnaire was sent to contacts from the Consortium for the Accreditation of Sonographic Education and details distributed at the British Medical Ultrasound Society conference in 2011. 116 responses were received from a range of clinical staff, with an interest in ultrasound assessment. The majority of respondents suggested that competency assessments should take place in the clinical departments with or without an element of assessment at the education centre. Moderation was an important area highlighted by respondents, with 84% of respondents suggesting two assessors were required and 66% of those stating some element of external moderation should be included. The findings suggest that respondentsâ preference is for some clinical competency assessments to take place on routine lists within the clinical department, assessed by two people one of which would be an external assessor. In view of recent reports relating to training and assessment of health care professionals, the ultrasound profession needs to begin the debate about how best to assess clinical competence and ensure appropriate first post competency of anyone undertaking ultrasound examinations
Identification of high risk patients with hypertrophic cardiomyopathy in a northern Greek population
This is an Open Access article distributed under the terms of the Creative Commons Attribution Licens
Improvement of convective drying of carrot by applying power ultrasound. Influence of mass load density
[EN] Power ultrasound is considered to be a novel and promising
technology with which to improve heat and mass transfer phenomena
in drying processes. The aim of this work was to contribute to the
knowledge of ultrasound application to air drying by addressing
the influence of mass load density on the ultrasonically assisted air
drying of carrot. Drying kinetics of carrot cubes were carried out
(in triplicate) with or without power ultrasound application (75 W,
21.7 kHz) at 40 C, 1 m/s, and several mass load densities: 12, 24,
36, 42, 48, 60, 72, 84, 96, 108, and 120 kg/m3
. The experimental
results showed a significant (p < 0.05) influence of both factors, mass
load density and power ultrasound application, on drying kinetics. As
expected, the increase of mass load density did not affect the effective
moisture diffusivity (De, m2
/s) but produced a reduction of the
mass transfer coefficient (k, kg water/m2
/s). This was explained by
considering perturbations in the air flow through the drying chamber
thus creating preferential pathways and, as a consequence, increasing
external mass transfer resistance. On the other hand, it was
found that the power ultrasound application increased the mass
transfer coefficient and the effective moisture diffusivity regardless
of the mass load density used. However, the influence of power ultrasound
was not significant at the highest mass load densities tested
(108 and 120 kg/m3
), which may be explained from the high ratio
(acoustic energy/sample mass) found under those experimental
conditions. Therefore, the application of ultrasound was considered
as a useful technology with which to improve the convective drying,
although its effects may be reduced at high mass load densities.The authors acknowledge the financial support of the Spanish Ministry of Science and Technology (DPI2009-14549-C04-04) and the Universidad Politecnica de Valencia (PAID-06-08-3180).CĂĄrcel CarriĂłn, JA.; GarcĂa PĂ©rez, JV.; Riera, E.; Mulet Pons, A. (2011). Improvement of convective drying of carrot by applying power ultrasound. Influence of mass load density. Drying Technology. 29(2):174-182. https://doi.org/10.1080/07373937.2010.483032S17418229
Ultrasonography of Quadriceps Femoris Muscle and Subcutaneous Fat Tissue and Body Composition by BIVA in Chronic Dialysis Patients
Protein Energy Wasting (PEW) in hemodialysis (HD) patients is a multifactorial condition due to specific pathology-related pathogenetic mechanisms, leading to loss of skeletal muscle mass in HD patients. Computed Tomography and Magnetic Resonance Imaging still represent the gold standard techniques for body composition assessment. However, their widespread application in clinical practice is difficult and body composition evaluation in HD patients is mainly based on conventional anthropometric nutritional indexes and bioelectrical impedance vector analysis (BIVA). Little data is currently available on ultrasound (US)-based measurements of muscle mass and fat tissue in this clinical setting. The purpose of our study is to ascertain: (1) if there are differences between quadriceps rectus femoris muscle (QRFM) thickness and abdominal/thigh subcutaneous fat tissue (SFT) measured by US between HD patients and healthy subjects; (2) if there is any correlation between QRFM and abdominal/thigh SFT thickness by US, and BIVA/conventional nutritional indexes in HD patients. We enrolled 65 consecutive HD patients and 33 healthy subjects. Demographic and laboratory were collected. The malnutrition inflammation score (MIS) was calculated. Using B-mode US system, the QRFM and SFT thicknesses were measured at the level of three landmarks in both thighs (superior anterior iliac spine, upper pole of the patella, the midpoint of the tract included between the previous points). SFT was also measured at the level of the periumbilical point. The mono frequency (50 KHz) BIVA was conducted using bioelectrical measurements (Rz, resistance; Xc, reactance; adjusted for height, Rz/H and Xc/H; PA, phase angle). 58.5% were men and the mean age was 69 (SD 13.7) years. QRFM and thigh SFT thicknesses were reduced in HD patients as compared to healthy subjects (p < 0.01). Similarly, also BIVA parameters, expression of lean body mass, were lower (p < 0.001), except for Rz and Rz/H in HD patients. The average QRFM thickness of both thighs at top, mid, lower landmarks were positively correlated with PA and body cell mass (BCM) by BIVA, while negatively correlated with Rz/H (p < 0.05). Abdominal SFT was positively correlated with PA, BCM and basal metabolic rate (BMR) (p < 0.05). Our study shows that ultrasound QRFM and thigh SFT thicknesses were reduced in HD patients and that muscle ultrasound measurements were significantly correlated with BIVA parameters
Outcome of fetuses with prenatal diagnosis of isolated severe bilateral ventriculomegaly: A systematic review and meta-analysis.
Objective
To quantify from the published literature survival and neurodevelopmental outcome of fetuses with prenatally detected isolated severe bilateral ventriculomegaly.
Methods
MEDLINE, EMBASE and the Cochrane Library were searched electronically. Only cases with a prenatal diagnosis of apparently isolated severe ventriculomegaly and postnatal neurodevelopmental assessment were selected and included. Severe ventriculomegaly was defined as enlargement of the ventricular atria, with a diameter of greater than 15âmm in the transventricular plane. All cases in which the investigators were unable to detect associated structural abnormality, chromosomal abnormality or fetal infection, and in which the ventriculomegaly was therefore regarded as apparently isolated, were included. Those for which the etiology was identified prenatally were excluded, whereas those with postnatal identification of the underlying cause were not excluded, since this information was not available prenatally. The quality of the included studies was assessed using the NewcastleâOttawa Scale (NOS) for cohort studies. Pregnancy outcomes such as termination, stillbirth, neonatal survival and developmental outcome of the baby, were recorded. The degree of disability was classified as no, mild or severe disability. Statistical assessment was performed by metaâanalysis of proportions to combine data, weighting the studies using the inverse variance method and a randomâeffects model. Proportions and CIs were reported.
Results
Eleven studies including 137 fetuses were found. Twentyâseven pregnancies underwent termination and were excluded. The remaining 110 fetuses with apparently isolated severe ventriculomegaly for which continuation of pregnancy was intended, form the study population. Overall quality assessed using NOS for cohort studies was good. Survival was reported in 95/110 (pooled proportion 87.9% (95% CI, 75.6â96.2%)) cases. In 15/110 (pooled proportion 12.1% (95% CI, 3.8â24.4%)), either stillbirth or neonatal demise was reported. No disability was reported in 41/95 survivors (pooled proportion 42.2% (95% CI, 27.5â57.6%)). However, 17/95 showed mild/moderate disability (pooled proportion 18.6% (95% CI, 7.2â33.8%)) and 37/95 were reported to have severe disability (pooled proportion 39.6% (95% CI, 30.0â50.0%)).
Conclusions
Fourâfifths of fetuses with severe ventriculomegaly survive and, of these, just over twoâfifths show normal neurodevelopment. The overall survivors without disability account for more than one third of the total. Given that many cases undergo termination of pregnancy and require longer followâup in order to detect subtle abnormalities, mortality and prevalence of developmental delay may be even higher than that reported in this paper
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