scholarly journals NO-HYPE: a novel hydrodynamic phantom for the evaluation of MRI flow measurements

2021 ◽  
Author(s):  
Giacomo Gadda ◽  
Sirio Cocozza ◽  
Mauro Gambaccini ◽  
Angelo Taibi ◽  
Enrico Tedeschi ◽  
...  
Keyword(s):  
Soft Tissues ◽  
Flow Profile ◽  
Hydraulic Pump ◽  
Flow Measurements ◽  
Blood Flows ◽  
Clinical Investigations ◽  
Phase Images ◽  
Mri Sequences ◽  
And Control ◽  
Flow Waveforms

Abstract Accurate and reproducible measurement of blood flow profile is very important in many clinical investigations for diagnosing cardiovascular disorders. Given that many factors could affect human circulation, and several parameters must be set to properly evaluate blood flows with phase-contrast techniques, we developed an MRI-compatible hydrodynamic phantom to simulate different physiological blood flows. The phantom included a programmable hydraulic pump connected to a series of pipes immersed in a solution mimicking human soft tissues, with a blood-mimicking fluid flowing in the pipes. The pump is able to shape and control the flow by driving a piston through a dedicated software. Periodic waveforms are used as input to the pump to move the fluid into the pipes, with synchronization of the MRI sequences to the flow waveforms. A dedicated software is used to extract and analyze flow data from magnitude and phase images. The match between the nominal and the measured flows was assessed, and the scope of phantom variables useful for a reliable calibration of an MRI system was accordingly defined. Results showed that the NO-HYPE phantom is a valuable tool for the assessment of MRI scanners and sequence design for the MR evaluation of blood flows. Graphical abstract

scholarly journals Effect of inspiratory flow waveforms on the mechanical work of ventilation; a fluid dynamic analysis

2020 ◽  
Author(s):  
Mojdeh Monjezi ◽  
Hamidreza Jamaati
Keyword(s):  
Dynamic Analysis ◽  
Tidal Volume ◽  
Fluid Dynamic ◽  
Inspiratory Flow ◽  
Mechanical Work ◽  
Flow Profile ◽  
Intensive Care Patients ◽  
Qualitative Conclusion ◽  
Sinusoidal Flow ◽  
Flow Waveforms

Abstract In most intensive care patients, the mechanical work (MW) is increased due to airway obstruction and/or tracheal intubation. Increasing MW is known as a risk factor for ventilator induced lung injury (VILI). Moeover, minimizing of MW is crucial to facilitate weaning process. In this paper MW is compared between three different inspiratory flow waveforms. The fluid dynamic analysis is used to compute the resistive pressure drop and the resistive work. We have compared square, sinusoidal and decelerating flow waveforms under the same tidal volume. The results show that under the constant tidal volume and I:E ratio, for tidal volumes below 1 lit, an square flow profile is beneficial for minimizing MW while a sinusoidal flow profile is prefered for tidal volumes of 1 lit or higher. It is shown that for make a decision about most beneficial flow profile in terms of less MW, both tidal volume and I:E ratio is important. By the way the results suggest to use decelerating flow waveforms with higher 1:E ratio. The qualitative conclusion is that in order to lower the MW especially in patients with obstructive lung diseases, sinusoidal, square and decelerating flow became preferable respectively with increasing I:E ratio. Our study suggest the square and sinusoidal profile for tidal volumes below and equal or over 1 lit, respectively in pointwiew of less MW. This paper also encouraged the engineers to add an option to select sinusoidal flow waveform in VCV mode to lower MW when tidal volume is l lit or higher.

scholarly journals Iontophoresis: principles and applications

2014 ◽  
Vol 27 (3) ◽  
pp. 469-481 ◽  
Author(s):  
Eddy Krueger ◽  
José Luiz Claudino Junior ◽  
Eduardo Mendonça Scheeren ◽  
Eduardo Borba Neves ◽  
Eduardo Mulinari ◽  
...  
Keyword(s):  
Soft Tissues ◽  
Prolonged Exposure ◽  
Electrical Current ◽  
Skin Layer ◽  
Google Scholar ◽  
Noninvasive Technique ◽  
Transdermal Penetration ◽  
And Control ◽  
Methods Of Treatment ◽  
Topical Applications

Introduction Iontophoresis is a noninvasive technique used to increase transdermal penetration of substances through the skin layer (epidermis, dermis and hypodermis) in a controlled manner. Technological advance in recent decades have provided reduced cost of equipment needed for implementation, which allowed for the expansion of this technique. Objective The aim of this paper is to present the state of the art on iontophoresis, ranging from the atomic characteristics of the ion formation to the current applications of the technique. Methods Were researched papers from databases: IOP publishing, ScienceDirect, Pubmed, Springer, IEEE Xplore, Google Scholar and books with keywords iontophoresis, ions, topical applications between 1967 and 2010. Results Were selected (number of papers and database) 1 IOP Publishing, 1 from ScienceDirect, Central, 1 from Springer, 2 from PubMed, 11 from IEEE Xplore, 35 from Google Scholar, and 15 books, totaling 66 references and websites with nationally marketed electrotherapy products. Conclusion Iontophoresis is suitable for applications such as acetic acid (calcific tendinitis and myositis ossificans), calcium chloride and magnesium sulfate (control of musculoskeletal spasms), dexamethasone (inflammation), lidocaine (inflammation of soft tissues), zinc oxide (rheumatoid arthritis). It is also used in cosmetic applications with devices attached to the skin and for eye treatment aimed at specific tissues of the eye, providing a treatment option for various eye diseases, reducing the complications secondary to traditional methods of treatment. The advantages are the significant increase in the release and control of therapeutic agents, including drugs with high molecular weight. The disadvantages of iontophoresis are the complexity of the drug release system and prolonged exposure of the skin to an electrical current.

Quantitative Analysis of Glabrous Skin Blood Flow and its Role in Human Thermoregulation

2012 ◽  
Author(s):  
Daniel W. Hensley ◽  
Andrew E. Mark ◽  
Eugene H. Wissler ◽  
Kenneth R. Diller
Keyword(s):  
Blood Flow ◽  
The Body ◽  
Glabrous Skin ◽  
Vascular Networks ◽  
Blood Flows ◽  
High Magnitude ◽  
Hairless Skin ◽  
Thermoregulatory System ◽  
And Control ◽  
Human Thermoregulation

Glabrous (hairless) skin found on the hands, feet, face, and ears is a unique component of the thermoregulatory system. Its anatomy and control physiology differ markedly from those of the rest of the skin. Glabrous regions contain vascular networks capable of supporting large blood flows due to the presence of highly tortuous and densely packed arteriovenous anastomoses (AVAs) and associated venous collecting networks [1]. When dilated, these vessels bring large volumes of blood close to the body surface where they function as highly efficient heat exchangers. Furthermore, the manner in which this blood flow is controlled is very unique, exhibiting, for example, rapid and high-magnitude responses, as well as a greater sensitivity to central core signals [1]. In this light, glabrous skin is an important but often overlooked tool the body uses to rapidly and finely adjust energy balance to maintain thermal equilibrium.

scholarly journals Impact of feeding male rats F2 with different doses of germanium citrate on the content of traceelements in their tissues and organs

2018 ◽  
Vol 5 (3) ◽  
pp. 40-46
Author(s):  
R. Fedoruk ◽  
U. Tesarivska ◽  
M. Khrabko ◽  
M. Tsap ◽  
H. Denys
Keyword(s):  
Soft Tissues ◽  
Positive Impact ◽  
Male Rats ◽  
Absolute Content ◽  
Muscle Tissues ◽  
Regulatory Impact ◽  
Organ Tissue ◽  
The Absolute ◽  
And Control ◽  
The Impact

Aim. To determine the impact of the dose of germanium citrate on the distribution of Fe, Zn, Cu, Co, Mn in tissues and organs of male F 2 rats. Methods. Physiological, biochemical, clinical, statistical. Results. It was established that there were changes in the content of Fe, Zn, Cu, Co, Mn in soft tissues and their distribution in liver, kidneys and lungs of male F 2 rats. It was demonstrated that these changes were mostly conditioned by organ-tissue specifi cities of functioning of some physiological systems of the organism, and less condition- ed – by the dose of germanium (10, 20 and 200 μg/kg of bodyweight). More vividly expressed changes in the content of these elements were established for kidneys at the effect of all the applied doses, and less express- ed – for liver and lungs. A positive impact of germanium citrate on the content of Cu, Co, Mn and Zn in the muscle tissues was determined at the effect of 10, 20 and 200 μg Ge, and as for Fe – 20 and 200 μg. The differences in the weight of liver, kidneys and lungs of rats of experimental and control groups were determined which eliminated the intergroup differences in the absolute content of the investigated microelements in liver, kidneys and lungs. The mentioned differences were more expressed for the absolute content of Cu in liver, Mn – in kidneys and lungs. Conclusions. Long-term introduction of germanium citrate into the organism of rats of generation F 2 with water in the amount of 10, 20 and 200 μg Ge/kg of the bodyweight is characterized by the changes in the content of Cu, Co, Mn, Fe, Zn both per one unit of soft tissue weight and their absolute content in the internal organs. The biological effect of germanium citrate is more expressed in the dose of 200 μg Ge/kg of the bodyweight, which conditions the increase in the content of Cu and Zn in all the investigated tissues of rats of this group at the background of the decreased level of Co in liver at the effect of 20 and 200 μg Ge, and at the effect of all the administered doses in kidneys and lungs. The level of Mn increased reliably in the muscle tissues of male F 2 rats at the effect of all the administered doses of Ge, Co 20 and 200 μg, Fe 10 and 20 μg, and Zn 10 and 200 μg Ge, which testifi es to the differences in the regulatory impact of NGeC on the level of investigated microelements in the muscle tissues of rats.

scholarly journals Imaging the Electro-Kinetic Response of Biological Tissues with Optical Coherence Tomography

2021 ◽  
Author(s):  
Valentin Demidov
Keyword(s):  
Optical Coherence Tomography ◽  
Soft Tissues ◽  
Low Frequency ◽  
Depth Resolution ◽  
Biological Tissues ◽  
Phase Changes ◽  
Optical Coherence ◽  
Ac Electric Field ◽  
Novel Approach ◽  
Phase Images

This thesis reports on developing a novel approach to imaging the electro-kinetic response of biological tissues with optical coherence tomography (OCT). The changes of backscattered OCT signal from tissues were investigated with a low frequency AC electric field being applied to the tissues. Advanced processing algorithms were developed to analyze the amplitude and phase changes of OCT signal. Two-dimensional electrically induced optical changes (EIOC) amplitude and phase images related to the electro-kinetic response of soft tissues were obtained with depth resolution and compared with structural OCT images. The procedure for removing the background noise from EIOC images was introduced.

scholarly journals Angiogenic Marker Alterations Following Enamel Matrix Derivative Treatment: A Human Study

2012 ◽  
Vol 2 (1) ◽  
pp. 8
Author(s):  
Onur Özçelik ◽  
Gülşah Seydaoğlu ◽  
Murat Cömert ◽  
Eftal Yılmaz ◽  
M. Cenk Haytaç
Keyword(s):  
Wound Healing ◽  
Inflammatory Infiltrate ◽  
Soft Tissues ◽  
Human Study ◽  
Gingival Tissue ◽  
Enamel Matrix Derivative ◽  
Enamel Matrix ◽  
And Control ◽  
Angiogenic Marker ◽  
Matrix Derivative

Aim: The aim of this immunohistochemical study was to assess the expression of angiogenic markers (vascular endothelial growth factor (VEGF) and microvessel density (MVD) in enamel matrix derivative (EMD) treated retromolar soft tissues to gain further insights into the biological mechanisms involved in wound healing and EMD treatment. Methodology: In twenty healthy volunteers, gingival biopsies were obtained from the distal wedge operations of test (EMD-applied) and control sites. EMD was applied into the test sites during the operation. At the 15th post-operative day, the sample sites were re-entered and gingival tissue samples were obtained from both test and control sites. A total of 80 samples for each sites were analyzed by immunohistochemistry for inflammatory infiltrate, expression of VEGF and MVD. Results: Despite similar post-operative inflammatory infiltrate, it was found that EMD- applied sites had statistically higher VEGF-A and VEGF-C expression and MVD compared to the controls on the 15th day. (p <0.0001 for each) Conclusions: This study supports that EMD has an angiogenic potential. The findings of this immunohistochemical analysis may help to gain insight into the angiogenic effects of EMD during the early phases of wound healing.  How to cite this article: Özçelik O, Seydaoğlu G, Cömert M, Yılmaz E, Haytaç MC. Angiogenic Marker Alterations Following Enamel Matrix Derivative Treatment: A Human Study. Int Dent Res 2012;2:8-16. Linguistic Revision: The English in this manuscript has been checked by at least two professional editors, both native speakers of English.

scholarly journals MRI flow measurements with a flexible stenosis phantom

2019 ◽  
Vol 5 (1) ◽  
pp. 565-568
Author(s):  
Alina Ibbeken ◽  
Pragathi Gurumurthy ◽  
Fenja Zell ◽  
Christina Hagen ◽  
Martin A. Koch ◽  
...  
Keyword(s):  
Magnetic Resonance Imaging ◽  
Soft Tissues ◽  
Upper Airway ◽  
Patient Specific ◽  
Resonance Imaging ◽  
Flow Conditions ◽  
Flow Measurements ◽  
Obstructive Sleep ◽  
Comparison And Analysis ◽  
Magnetic Resonance Imaging Mri

AbstractObstructive sleep apnea (OSA) is a common sleep disorder caused by the collapse of the upper airway during sleep due to a shift of soft tissues. To optimise the treatment, one needs a better understanding of the patient-specific causes of OSA. As a first step, a flexible tube with a stenosis was manufactured, representing a simple model of the pharynx geometry. The phantom has been used to carry out magnetic resonance imaging (MRI) flow sensitive measurements, to investigate the flow conditions that lead to the collapse. This contribution is concerned with the comparison and analysis of the flow and phantom deformation using varying boundary conditions, such as the Reynolds number and transmural pressure.

Time-related changes in microsphere entrapment in canine jejunum

1989 ◽  
Vol 256 (3) ◽  
pp. G451-G457
Author(s):  
I. Prokopiw ◽  
P. K. Dinda ◽  
I. T. Beck
Keyword(s):  
Blood Flow ◽  
Muscularis Propria ◽  
Fractional Flow ◽  
Flow Measurements ◽  
Blood Flows ◽  
Blood Flow Measurements

To assess the validity of repeated blood flow measurements using the microsphere technique, the apparent blood flows in the anatomic layers of the jejunum were determined from the entrapment of 9-, 11.5-, and 17-micron microspheres at 1.5, 15, 30, and 60 min after their injection. The entrapment of 17-micron spheres in the mucosa plus submucosa and in the muscularis propria remained similar at all times, but these spheres migrated (P less than 0.01) from the submucosa to the mucosa. By 1.5 min, 5 +/- 2% of 11.5-micron spheres had shunted, but no subsequent shunting was observed. No migration of 11.5-micron spheres from the mucosa, submucosa or the muscularis was observed. The shunting of 9-micron spheres from the whole wall increased from 19 +/- 4% at 1.5 min to 40 +/- 4% at 60 min (P less than 0.001). These data suggest that 17-micron spheres can only fractionate the blood flow of the whole wall into that of the mucosa plus submucosa and that of the muscularis propria, while 11.5-micron spheres may measure fractional flow to the submucosa separately. The continued washout of 9-micron microspheres precludes their use for repeated blood flow measurements.

The Effect of Duct Cross-Sectional Shapes on Metrological Performance of Ultrasonic Flowmeters

2007 ◽  
Author(s):  
Iryna Gryshanova
Keyword(s):  
Correction Factor ◽  
Fluid Velocity ◽  
Flow Characteristics ◽  
Optimum Shape ◽  
Flow Profile ◽  
Axially Symmetric ◽  
Cross Sectional ◽  
Flow Measurements ◽  
Profile Correction ◽  
Ultrasonic Time

This paper describes prospects of measuring range extension on transient and laminar flow regimes for ultrasonic time-of-flight flowmeters due to creation measuring ducts with special cross-sectional shapes. The appropriateness of this idea consists that the flow profile correction factor, which considers a difference between averaged fluid velocity along the path of ultrasound propagation and area-averaged fluid velocity is not identical for laminar, transitive and turbulent conditions. Even on the assumption of axially symmetric flows the correction factor changes more than on 25% at transition from one condition to another. In this connection there was an object in view how to eliminate the influence of a velocity profile on accuracy of ultrasonic flow measurements. For that computer models of ultrasonic meters with several variants of cross-sections have been developed and due to CFD techniques the flow profile sensitivities of various meter configurations are investigated in different Reynolds number flows. The selection of optimum shape of the measuring duct for ultrasonic flowmeters has been appraised based on getting of as much as possible stable correction factor in a wide flow range and the minimal pressure loss on a meter. Results show that ultrasonic flowmeters with specially designed duct shapes could be used for increasing accuracy of non-liquid meter calibration and also for elimination of the error caused by variations of hydrodynamic flow characteristics.

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