This study aims to validate the use of quantifying vascular permeability as an early diagnostic tool for diabetic retinopathy. Retinal videoangiography data from diabetic rats was analyzed using tracer kinetic modeling and linear systems theory to map blood flow volume and permeability. The results show increased permeability in diabetic rats, demonstrating its potential as a noninvasive, clinically translatable biomarker for early detection of diabetic retinopathy before irreversible damage occurs. Further research is still needed to refine the methodology.
This document discusses different types of intracardiac shunts including atrial septal defects (ASD), patent foramen ovale (PFO), and ventricular septal defects (VSD). It focuses on ASDs, describing the different types, symptoms, evaluation, and indications for intervention. Key points include:
1) The main types of ASDs are secundum, primum, and sinus venosus defects.
2) ASDs often cause no symptoms until adulthood and are diagnosed using echocardiography.
3) Evaluation includes assessing RV volume overload, measuring left-to-right shunting ratio (Qp/Qs), and determining pulmonary pressures.
This document discusses various methods for quantifying intracardiac shunts in patients with congenital heart lesions. It describes invasive oximetry and indicator dilution techniques as well as noninvasive Doppler echocardiography methods. For echocardiography, it outlines techniques for quantifying left-to-right shunts using pulmonary and aortic flow measurements, as well as a simplified method using diameter ratios. It also discusses limitations and sources of error for these quantification methods.
This 3-page document provides a review of theoretical and practical aspects for correctly measuring flow volume (Q) of arteriovenous fistulae (AVF) using duplex ultrasound. It discusses key technical concepts like the continuity equation for calculating Q, accuracy of diameter and area measurements, handling of cardiac cycle and Doppler angle effects. The document recommends standardizing Q measurement techniques and locations to reduce variability and enable meaningful comparisons between studies.
This document discusses the calculation of bidirectional shunts. It explains that a "shunt run" is performed if sampling between chambers shows an 8% difference in blood oxygen levels. It also discusses Flamm's equation for calculating mixed venous oxygen content, which factors in contributions from the inferior and superior vena cava. Additionally, it reviews the Fick equation for calculating oxygen content, which assumes steady state conditions where the rate of substance entering equals the rate leaving plus any added. Finally, it defines various terms used in calculating pulmonary blood flow, systemic blood flow, effective blood flow, and left-to-right and right-to-left shunt values.
Phase contrast MRI uses changes in the phase of tissue magnetization from moving protons to create angiographic images and measure flow velocity. ECG-gated MRI acquires images during systole and diastole, subtracting the former to highlight arteries based on their faster flow during cardiac contraction. Typical velocity encoding values are 20-30 cm/s for veins, 40-60 cm/s for higher arterial flow, and over 60 cm/s to determine flow direction and velocity.
Imaging in neurology - normal MR Angio and VenographyNeurologyKota
There are two main types of MR angiography (MRA): contrast-enhanced (CE) MRA and non-contrast enhanced MRA, which includes time-of-flight (TOF) MRA and phase contrast (PC) MRA. CE MRA uses an injected gadolinium contrast agent and is faster than non-contrast MRA. TOF MRA detects blood flow without contrast but is susceptible to artifacts. PC MRA measures blood velocity and flow direction and can quantify blood flow. MR venography (MRV) uses similar techniques as MRA to image veins and is useful for detecting cerebral venous thrombosis. Common applications of MRA and MRV include evaluation of aneurysms, neck vessels, and cerebral
This document discusses the use of coronary CT angiography to detect and characterize coronary artery anatomy and exclude morphological abnormalities. It notes the technique involves a preliminary scout study followed by contrast-enhanced imaging of the coronary arteries. Reconstructions include curved multi-planar views. The quality was deemed excellent with no artifacts. The impression was a total calcium score of zero, no evidence of stenosis or plaque, and a CAD-RADS classification of 0, recommending reassurance.
This research article evaluated the diagnostic power of cardiac MRI to detect pulmonary hypertension in patients pre-selected by echocardiography. Fifty-six patients suspected of pulmonary hypertension based on echocardiography underwent right heart catheterization and cardiac MRI. The study extracted various MRI parameters proposed in previous studies as surrogates for pulmonary arterial pressure. Multivariate regression analysis identified right ventricle ejection fraction and pulmonary trunk minimum area as predictors of mean pulmonary arterial pressure, with an r-squared value of 0.5. However, the limits of agreement between MRI-predicted and catheterization-measured pressures were too wide. MRI was able to distinguish patients with normal and elevated pressures, achieving a specificity of 80% for detecting pulmonary hypertension at
This document discusses different types of intracardiac shunts including atrial septal defects (ASD), patent foramen ovale (PFO), and ventricular septal defects (VSD). It focuses on ASDs, describing the different types, symptoms, evaluation, and indications for intervention. Key points include:
1) The main types of ASDs are secundum, primum, and sinus venosus defects.
2) ASDs often cause no symptoms until adulthood and are diagnosed using echocardiography.
3) Evaluation includes assessing RV volume overload, measuring left-to-right shunting ratio (Qp/Qs), and determining pulmonary pressures.
This document discusses various methods for quantifying intracardiac shunts in patients with congenital heart lesions. It describes invasive oximetry and indicator dilution techniques as well as noninvasive Doppler echocardiography methods. For echocardiography, it outlines techniques for quantifying left-to-right shunts using pulmonary and aortic flow measurements, as well as a simplified method using diameter ratios. It also discusses limitations and sources of error for these quantification methods.
This 3-page document provides a review of theoretical and practical aspects for correctly measuring flow volume (Q) of arteriovenous fistulae (AVF) using duplex ultrasound. It discusses key technical concepts like the continuity equation for calculating Q, accuracy of diameter and area measurements, handling of cardiac cycle and Doppler angle effects. The document recommends standardizing Q measurement techniques and locations to reduce variability and enable meaningful comparisons between studies.
This document discusses the calculation of bidirectional shunts. It explains that a "shunt run" is performed if sampling between chambers shows an 8% difference in blood oxygen levels. It also discusses Flamm's equation for calculating mixed venous oxygen content, which factors in contributions from the inferior and superior vena cava. Additionally, it reviews the Fick equation for calculating oxygen content, which assumes steady state conditions where the rate of substance entering equals the rate leaving plus any added. Finally, it defines various terms used in calculating pulmonary blood flow, systemic blood flow, effective blood flow, and left-to-right and right-to-left shunt values.
Phase contrast MRI uses changes in the phase of tissue magnetization from moving protons to create angiographic images and measure flow velocity. ECG-gated MRI acquires images during systole and diastole, subtracting the former to highlight arteries based on their faster flow during cardiac contraction. Typical velocity encoding values are 20-30 cm/s for veins, 40-60 cm/s for higher arterial flow, and over 60 cm/s to determine flow direction and velocity.
Imaging in neurology - normal MR Angio and VenographyNeurologyKota
There are two main types of MR angiography (MRA): contrast-enhanced (CE) MRA and non-contrast enhanced MRA, which includes time-of-flight (TOF) MRA and phase contrast (PC) MRA. CE MRA uses an injected gadolinium contrast agent and is faster than non-contrast MRA. TOF MRA detects blood flow without contrast but is susceptible to artifacts. PC MRA measures blood velocity and flow direction and can quantify blood flow. MR venography (MRV) uses similar techniques as MRA to image veins and is useful for detecting cerebral venous thrombosis. Common applications of MRA and MRV include evaluation of aneurysms, neck vessels, and cerebral
This document discusses the use of coronary CT angiography to detect and characterize coronary artery anatomy and exclude morphological abnormalities. It notes the technique involves a preliminary scout study followed by contrast-enhanced imaging of the coronary arteries. Reconstructions include curved multi-planar views. The quality was deemed excellent with no artifacts. The impression was a total calcium score of zero, no evidence of stenosis or plaque, and a CAD-RADS classification of 0, recommending reassurance.
This research article evaluated the diagnostic power of cardiac MRI to detect pulmonary hypertension in patients pre-selected by echocardiography. Fifty-six patients suspected of pulmonary hypertension based on echocardiography underwent right heart catheterization and cardiac MRI. The study extracted various MRI parameters proposed in previous studies as surrogates for pulmonary arterial pressure. Multivariate regression analysis identified right ventricle ejection fraction and pulmonary trunk minimum area as predictors of mean pulmonary arterial pressure, with an r-squared value of 0.5. However, the limits of agreement between MRI-predicted and catheterization-measured pressures were too wide. MRI was able to distinguish patients with normal and elevated pressures, achieving a specificity of 80% for detecting pulmonary hypertension at
Voor de toevoer van water, lucht, zuurstof, medische
gassen en chemicaliën zijn veilige en betrouwbare
componenten van levensbelang. Logisch dus dat aan
deze componenten hoge eisen worden gesteld.
IFC has appointed White Lotus Centre Pvt. Ltd. as the fund manager for Business Oxygen, IFC's $14 million SME ventures fund in Nepal. Business Oxygen is Nepal's first private equity fund, with IFC committing $7 million. The fund will make equity investments in high-growth SMEs in Nepal and provide them advisory support to help develop their operations and contribute to Nepal's economic growth. White Lotus aims to develop a robust portfolio of investee firms through Business Oxygen.
Este documento proporciona una guía sobre las funciones y herramientas básicas de Microsoft Word. Explica las barras de herramientas y menús, cómo cambiar entre ventanas y documentos, guardar y cerrar archivos, usar el portapapeles, insertar ecuaciones y seleccionar texto. También describe cómo deshacer y rehacer acciones, buscar y reemplazar texto, abrir múltiples documentos simultáneamente, y trabajar con errores ortográficos y de puntuación. Por último, explica cómo agregar y elim
Six accelerometers in each football helmet measure impact forces and wirelessly transmit the data to an Android device for analysis. An algorithm determines the likelihood and location of concussion based on the impact. The Android app alerts coaches in real-time and stores the data on a server. Testing showed the system accurately locates impacts within 30 degrees and identifies risks with a low error rate.
1) The document describes a study that aimed to develop a continuous and non-invasive method of measuring blood pressure using ultrasound.
2) The method uses Doppler and B-mode ultrasound to measure blood velocity and arterial diameter in the brachial artery. These measurements are then used to calculate differential pressure, which is correlated to actual blood pressure readings from a sphygmomanometer.
3) The study first proved this correlation using a phantom model of the brachial artery, then measured blood pressure in 26 healthy patients to establish an in vivo standard correlation curve. This curve can be used to determine blood pressure from ultrasound measurements of differential pressure.
The document outlines a database schema for tracking clinical skills equipment for a clinical skills center, including tables for equipment specifications, locations, items, borrowers, loans, rooms, skills, equipment-skill relationships, and equipment pictures. Fields include equipment name, manufacturer, description, manual, and picture indexes to store multiple views of equipment. The schema aims to manage equipment inventory, locations, borrowing and loan tracking, and equipment-skill associations.
Bloodless Haemoglobin level Detection using Deep Convolution Neural NetworkIRJET Journal
This document describes a proposed system to detect haemoglobin levels non-invasively using deep learning techniques. The system would use a deep convolutional neural network (DCNN) trained on images of participants' conjunctiva taken with a smartphone camera. The DCNN would be trained to predict numeric haemoglobin values by comparing them to validated complete blood count (CBC) reports. The goal is to develop an accurate, non-invasive method for real-time haemoglobin detection to help diagnose anaemia and other conditions. The proposed system aims to explore how well a DCNN can detect haemoglobin levels compared to existing non-invasive techniques.
This study examined the relationship between volume overhydration and endothelial dysfunction in 81 stable patients on continuous ambulatory peritoneal dialysis. Volume status was assessed by normalized extracellular water and endothelial function was estimated by flow-mediated dilation of the brachial artery. There was an independent correlation between the index of volume status (normalized extracellular water) and endothelial function (flow-mediated dilation), with higher normalized extracellular water related to worse endothelial function. Multiple regression analysis identified calcium-phosphate product, normalized extracellular water, and dialysis vintage as independent determinants of endothelial function. The results suggest that volume overhydration may lead to increased cardiovascular risk in dialysis patients through its effects on endothelial dysfunction.
This document proposes a new method for monitoring heart failure by measuring venous distension using a catheter. It describes developing a computational model and in-vitro model to test the relationship between resistivity measurements from a catheter and venous diameter. The catheter would be placed long-term in a large vein. An algorithm was created to estimate resistivity from the catheter measurements and calculate the vein radius. Testing in a simulated vein using saline and blood showed the algorithm could estimate the radius with less than 2.5% error. This new approach may allow reliable estimation of venous distension as an indirect measure of heart failure severity.
Hemodynamic monitoring of critically ill patientsV4Veeru25
Hemodynamic monitoring measures blood pressure, blood flow, and oxygen levels in the veins, heart, and arteries to provide information about a patient's circulation, perfusion, and organ oxygenation. It can be done invasively, using catheters in arteries or veins to directly measure pressures, or non-invasively using tools like a blood pressure cuff. Common invasive monitors include arterial lines, central venous pressure monitors, and pulmonary artery catheters. Precise readings and interpretations along with nursing care of lines and dressings are important for effective hemodynamic monitoring of critically ill patients.
The document discusses various techniques for hemodynamic monitoring, including both conventional and advanced methods. It provides an overview of the history of hemodynamic monitoring and outlines some of the goals of different monitoring devices. The document then reviews several specific monitoring techniques, such as arterial lines, central venous catheters, pulmonary artery catheters, echocardiography, pulse contour analysis, and electrical bioimpedance. Both advantages and disadvantages of each method are discussed.
Echocardiography to assess Fluid Responsiveness in icuDr.Mahmoud Abbas
Here are some potential recommendations for training intensivists in basic echocardiography for fluid management:
- Define core competencies for basic echocardiography focused on fluid assessment (e.g. IVC size, LVOT VTI, SV variation)
- Require a minimum number of didactic lectures/courses on echocardiography physiology and techniques
- Mandate hands-on training with a structured curriculum using simulators and proctored exams on patients
- Intensivists should be able to obtain basic views, make measurements accurately and interpret dynamic parameters
- Continuing education requirements (e.g. minimum exams/scans per year) to maintain competency
- Certification process
This research article compares four different methods for correcting myocardial signal intensity (SI) saturation in first-pass perfusion magnetic resonance imaging (MRI) to calculate accurate absolute myocardial blood flow (MBF) values. The study involved performing MRI on dogs undergoing vasodilation and varying degrees of simulated coronary stenosis. MBF was calculated using the uncorrected MRI SI data and data corrected using two theoretical and two empirically derived correction methods, and these values were compared to MBF measured using microspheres (the gold standard). All correction methods improved the correlation with microspheres compared to uncorrected MRI data. The empirically derived methods resulted in MBF values closest to microspheres and avoided underestimation at higher flows, suggesting myocardial
This document discusses using quantitative Doppler echocardiography (DE) to assess cardiac preload, volume status, and hemodynamics in patients with acute heart failure. DE can noninvasively measure stroke volume, left ventricular filling pressure, and right ventricular systolic pressure to identify mismatches between the right and left sides of the heart. Serial DE measurements can help guide fluid management and titrate therapies in real-time. Case studies demonstrate how DE can optimize preload and guide care for different clinical scenarios. Wider adoption of quantitative DE in heart failure management may help improve outcomes, but challenges around standardization and interpretation need to be addressed.
Voor de toevoer van water, lucht, zuurstof, medische
gassen en chemicaliën zijn veilige en betrouwbare
componenten van levensbelang. Logisch dus dat aan
deze componenten hoge eisen worden gesteld.
IFC has appointed White Lotus Centre Pvt. Ltd. as the fund manager for Business Oxygen, IFC's $14 million SME ventures fund in Nepal. Business Oxygen is Nepal's first private equity fund, with IFC committing $7 million. The fund will make equity investments in high-growth SMEs in Nepal and provide them advisory support to help develop their operations and contribute to Nepal's economic growth. White Lotus aims to develop a robust portfolio of investee firms through Business Oxygen.
Este documento proporciona una guía sobre las funciones y herramientas básicas de Microsoft Word. Explica las barras de herramientas y menús, cómo cambiar entre ventanas y documentos, guardar y cerrar archivos, usar el portapapeles, insertar ecuaciones y seleccionar texto. También describe cómo deshacer y rehacer acciones, buscar y reemplazar texto, abrir múltiples documentos simultáneamente, y trabajar con errores ortográficos y de puntuación. Por último, explica cómo agregar y elim
Six accelerometers in each football helmet measure impact forces and wirelessly transmit the data to an Android device for analysis. An algorithm determines the likelihood and location of concussion based on the impact. The Android app alerts coaches in real-time and stores the data on a server. Testing showed the system accurately locates impacts within 30 degrees and identifies risks with a low error rate.
1) The document describes a study that aimed to develop a continuous and non-invasive method of measuring blood pressure using ultrasound.
2) The method uses Doppler and B-mode ultrasound to measure blood velocity and arterial diameter in the brachial artery. These measurements are then used to calculate differential pressure, which is correlated to actual blood pressure readings from a sphygmomanometer.
3) The study first proved this correlation using a phantom model of the brachial artery, then measured blood pressure in 26 healthy patients to establish an in vivo standard correlation curve. This curve can be used to determine blood pressure from ultrasound measurements of differential pressure.
The document outlines a database schema for tracking clinical skills equipment for a clinical skills center, including tables for equipment specifications, locations, items, borrowers, loans, rooms, skills, equipment-skill relationships, and equipment pictures. Fields include equipment name, manufacturer, description, manual, and picture indexes to store multiple views of equipment. The schema aims to manage equipment inventory, locations, borrowing and loan tracking, and equipment-skill associations.
Bloodless Haemoglobin level Detection using Deep Convolution Neural NetworkIRJET Journal
This document describes a proposed system to detect haemoglobin levels non-invasively using deep learning techniques. The system would use a deep convolutional neural network (DCNN) trained on images of participants' conjunctiva taken with a smartphone camera. The DCNN would be trained to predict numeric haemoglobin values by comparing them to validated complete blood count (CBC) reports. The goal is to develop an accurate, non-invasive method for real-time haemoglobin detection to help diagnose anaemia and other conditions. The proposed system aims to explore how well a DCNN can detect haemoglobin levels compared to existing non-invasive techniques.
This study examined the relationship between volume overhydration and endothelial dysfunction in 81 stable patients on continuous ambulatory peritoneal dialysis. Volume status was assessed by normalized extracellular water and endothelial function was estimated by flow-mediated dilation of the brachial artery. There was an independent correlation between the index of volume status (normalized extracellular water) and endothelial function (flow-mediated dilation), with higher normalized extracellular water related to worse endothelial function. Multiple regression analysis identified calcium-phosphate product, normalized extracellular water, and dialysis vintage as independent determinants of endothelial function. The results suggest that volume overhydration may lead to increased cardiovascular risk in dialysis patients through its effects on endothelial dysfunction.
This document proposes a new method for monitoring heart failure by measuring venous distension using a catheter. It describes developing a computational model and in-vitro model to test the relationship between resistivity measurements from a catheter and venous diameter. The catheter would be placed long-term in a large vein. An algorithm was created to estimate resistivity from the catheter measurements and calculate the vein radius. Testing in a simulated vein using saline and blood showed the algorithm could estimate the radius with less than 2.5% error. This new approach may allow reliable estimation of venous distension as an indirect measure of heart failure severity.
Hemodynamic monitoring of critically ill patientsV4Veeru25
Hemodynamic monitoring measures blood pressure, blood flow, and oxygen levels in the veins, heart, and arteries to provide information about a patient's circulation, perfusion, and organ oxygenation. It can be done invasively, using catheters in arteries or veins to directly measure pressures, or non-invasively using tools like a blood pressure cuff. Common invasive monitors include arterial lines, central venous pressure monitors, and pulmonary artery catheters. Precise readings and interpretations along with nursing care of lines and dressings are important for effective hemodynamic monitoring of critically ill patients.
The document discusses various techniques for hemodynamic monitoring, including both conventional and advanced methods. It provides an overview of the history of hemodynamic monitoring and outlines some of the goals of different monitoring devices. The document then reviews several specific monitoring techniques, such as arterial lines, central venous catheters, pulmonary artery catheters, echocardiography, pulse contour analysis, and electrical bioimpedance. Both advantages and disadvantages of each method are discussed.
Echocardiography to assess Fluid Responsiveness in icuDr.Mahmoud Abbas
Here are some potential recommendations for training intensivists in basic echocardiography for fluid management:
- Define core competencies for basic echocardiography focused on fluid assessment (e.g. IVC size, LVOT VTI, SV variation)
- Require a minimum number of didactic lectures/courses on echocardiography physiology and techniques
- Mandate hands-on training with a structured curriculum using simulators and proctored exams on patients
- Intensivists should be able to obtain basic views, make measurements accurately and interpret dynamic parameters
- Continuing education requirements (e.g. minimum exams/scans per year) to maintain competency
- Certification process
This research article compares four different methods for correcting myocardial signal intensity (SI) saturation in first-pass perfusion magnetic resonance imaging (MRI) to calculate accurate absolute myocardial blood flow (MBF) values. The study involved performing MRI on dogs undergoing vasodilation and varying degrees of simulated coronary stenosis. MBF was calculated using the uncorrected MRI SI data and data corrected using two theoretical and two empirically derived correction methods, and these values were compared to MBF measured using microspheres (the gold standard). All correction methods improved the correlation with microspheres compared to uncorrected MRI data. The empirically derived methods resulted in MBF values closest to microspheres and avoided underestimation at higher flows, suggesting myocardial
This document discusses using quantitative Doppler echocardiography (DE) to assess cardiac preload, volume status, and hemodynamics in patients with acute heart failure. DE can noninvasively measure stroke volume, left ventricular filling pressure, and right ventricular systolic pressure to identify mismatches between the right and left sides of the heart. Serial DE measurements can help guide fluid management and titrate therapies in real-time. Case studies demonstrate how DE can optimize preload and guide care for different clinical scenarios. Wider adoption of quantitative DE in heart failure management may help improve outcomes, but challenges around standardization and interpretation need to be addressed.
Value Analysis Committee Presentation - PleuraFlow® ACT® SystemPaul Molloy
Presentation explaining how the PleuraFlow® ACT® System from ClearFlow,Inc.can Reduce Complications and Costs for your Cardiothoracic surgery patients.
This document discusses using intrathoracic impedance measures from implantable cardiac devices to monitor changes in intravascular fluid volume during volume reduction therapy for heart failure patients. It found that two impedance vectors, between the right atrial ring to left ventricular ring and the left ventricular ring to right ventricular ring, were most closely associated with changes in plasma volume as measured by hematocrit levels. Monitoring these specific impedance vectors may help more accurately guide volume reduction therapy by tracking changes in the intravascular fluid compartment.
This document describes a reference method recommended by the International Council for Standardization in Haematology (ICSH) and the International Society of Laboratory Hematology (ISLH) for platelet counting. The method involves labeling platelets in fresh blood samples with fluorescent antibodies and counting the labeled platelets relative to red blood cells using flow cytometry. An accurate red blood cell count is also determined on the original sample. The ratio of red blood cells to platelets obtained from the flow cytometry data is used along with the red blood cell count to calculate the platelet count. The method provides accurate and precise results needed for calibration of hematology analyzers.
This study assessed the accuracy of arterial pressure waveform analysis (APCO) for measuring cardiac output in patients requiring high-dose vasopressor therapy for cerebral vasospasm. The study compared APCO measurements from the FloTrac/Vigileo device to transpulmonary thermodilution cardiac output (TPCO) measurements in 24 patients. Patients received high doses of norepinephrine, resulting in high mean arterial pressure and systemic vascular resistance. APCO measurements showed poor precision compared to TPCO, with a bias and limits of agreement of 0.9 L/min and 2.5 L/min, respectively. The precision of APCO varied inversely with systemic vascular resistance and was not improved by updating to a newer
Study on viscosity induced contrast in ultrasound color flow imaging of carot...IJECEIAES
Efficient imaging of blood flow disturbances resulted from carotid atherosclerosis plays a vital role clinically to predict brain stroke risk. Carotid atherosclerosis and its development is closely linked with raised blood viscosity. Therefore, study of viscosity changing hemodynamic effect has importance and it might be useful for improved examination of carotid atherosclerosis incorporating the viscosity induced contrast in conventional ultrasound imaging. This work considered the design of realistic models of atherosclerotic carotid artery of different stages and solved to compute the hemodisturbances using computational fluid dynamics (CFD) by finite element method (FEM) to investigate viscosity changes effect. Ultrasound color flow image of velocities of blood have been constructed using phase shift information estimated with autocorrelation of Hilbert transformed simulated backscattered radiofrequency (RF) signals from moving blood particles. The simulated ultrasound images have been compared with CFD simulation images and identified a good match between them. The atherosclerosis stages of the models have been investigated from the estimated velocity data. It has been observed that the blood velocities increase noticeably in carotid atherosclerotic growths and velocity distribution changes with viscosity variations. It is also found importantly that the viscosity induced contrast associated to atherosclerosis is detectable in ultrasound color flow imaging. The findings of this work might be useful for better investigation of carotid atherosclerosis as well as prediction of its progression to reduce the stroke risk.
1. The document discusses various questions about how the Starling device measures stroke volume variation, cardiac output, and other hemodynamic parameters noninvasively using bioreactance technology.
2. It provides details on studies that have validated Starling against invasive hemodynamic monitoring techniques. Starling can be used in various clinical settings such as the operating room and intensive care.
3. The document addresses limitations and appropriate use of the Starling device and sensors. It clarifies differences between bioreactance and bioimpedance technologies.
This document reviews various techniques for detecting blood vessels in retinal images. It discusses local entropy thresholding, matched filter methods, and Gaussian mixture models. Local entropy thresholding aims to maximize local entropy to extract vessels, but some structures may be missed. Matched filtering uses kernels to enhance vessels, but thin vessels can be hard to detect. Gaussian mixture models use expectation maximization to classify pixels into vessel and non-vessel classes. Other discussed techniques include fuzzy C-means clustering, Gabor wavelets, Hough transforms, and neural networks. Each technique has benefits but also limitations regarding preprocessing requirements, computation time, and ability to detect different vessel structures.
Supratentorial intracerebral hemorrhage volume and other CT variables predict...NeurOptics, Inc.
However, it is not practical to obtain repeated serial CT scans in ICH patients to assess for these factors. A noninvasive indicator method of assessing the aforementioned factors would be very useful and could serve as a trigger for repeating a CT scan in a patient with ICH.
This document discusses several studies on the use of intracoronary imaging and physiology techniques. It summarizes guidelines on using these techniques from 2014 and discusses studies showing their value in better understanding prognosis, simplifying assessment, and their potential value in STEMI. Specific studies discussed include ones analyzing FFR as a continuous risk marker, evaluating iFR and other techniques, comparing FFR and contrast injection, co-registering angiography with intracoronary imaging, using physiology mapping, and exploring the use of physiology techniques to anticipate microvascular injury after PCI for STEMI.
Reunion Anual Madeira 2015 Imagen y análisis funcional intracoronarios
ArmourRD_Poster_Adriane_Walther
1.
Valida'on
of
vascular
permeability
as
preclinical
diagnos'c
tool
for
diabe'c
re'nopathy
using
fluorescein
videoangiography
tracer
kine'cs
Adriane
Walther,
Kenneth
M.
Tichauer,
Jennifer
J.
Kang-‐Mieler,
BME,
Theme:
Health
Introduc?on
Purpose
Theory
Methods
Results
Diabe?c
re?nopathy
is
characterized
by
abnormal
hemodynamics
in
the
neovasculature
of
the
eye
is
not
detectable
un?l
it
reaches
an
irreversible
stage,
at
least
by
today’s
treatment
standards.
Therefore,
methods
of
detec?on
for
its
onset
are
in
demand.
This
study
aims
to
use
an
adiaba?c
approxima?on
to
?ssue
homogeneity
model
and
tracer
kine?c
modeling
to
validate
the
quan?fica?on
of
vascular
permeability
as
a
“sub-‐clinical”
diagnos?c
tool
of
diabe?c
re?nopathy.
Re?nal
videoangiographic
data,
using
fluorescein
as
a
radiopaque
tracer,
obtained
from
diabetes
induced
rats
was
evaluated
to
validate
the
capacity
of
vascular
permeability
as
an
early
indicator
of
diabe?c
re?nopathy.
In
this
study,
a
method
for
quan?ta?vely
mapping
volumetric
flow
and
re?nal
permeability
using
fluorescein
videoangiography
is
proposed
using
tracer
kine?c
modeling
and
the
theories
of
linear
systems
theory.
dCf (t)
dt
= −keCf (t)
)()()( thtFCtFC av ∗=
Q(t) = F Ca (u)du−
0
t
∫ F Ca (u)∗h(u)du
0
t
∫
Q(t) = FCa (t)∗ R(t)
R(t) =1− h(u)du
0
t
∫
Adiaba&c
Approxima&on
to
the
Tissue
Homogeneity
Model
The
concentra?on
of
imaging
agent,
Q(t),
was
treated
as
a
black-‐box
model
with
arterial
input
and
venous
output
func?on.
The
input
is
defined
as
product
of
the
volumetric
flow,
F,
and
the
upflow
of
arterial
blood
flow,
Ca(t),
called
the
arterial
input
func?on
while
the
output
is
defined
as
the
product
of
the
volumetric
flow
and
the
ouRake
of
venous
blood
flow.
where
*
represents
the
convolu?on
operator.
Linear
Systems
Theory
By
linear
systems
theory,
the
output
can
also
be
defined
as
the
convolu?on
of
the
arterial
input
func?on
with
the
func?onal
response
of
the
system
to
a
Dirac
Delta
func?on,
h(t).
Then,
by
the
law
of
conserva?on
of
mass,
the
concentra?on
of
fluorescein
in
the
vessels
is
equal
to
the
difference
of
the
input
and
output
func?ons.
where u represents a dummy integra?on variable. This can then be simplified to:
where
R(t)
is
the
impulse
residue
func?on,
defined
as:
Plug
Flow
Model
Because
the
ini?al
value
of
R(t)
must
equal
1,
because
h(0)=0,
it
can
be
said
that
FR(t)
is
equivalent
to
the
volumetric
blood
flow,
F.
Furthermore,
the
dynamics
of
the
fluorescein
concentra?on
is
used
to
approximate
the
leakage
of
blood
out
of
the
vessels
and
into
extravascular
?ssue,
“extrac?on
frac?on”
E,
by
assuming
a
“plug-‐flow”
model
sta?ng
that
the
rate
at
which
imagining
agent
is
washed
out
of
the
?ssue
and
back
into
the
blood
stream
can
be
represented
by
a
first
order
equa?on:
where
ke
is
a
constant
rela?ng
the
efflux
back
into
the
vessel.
Streptozocin-‐induced
Long-‐Evans
rats
were
anesthe?zed
with
ketamine
(80
mg/kg
BW)
and
xylazine
(10
mg.kg
BW)
through
the
tail
vein
and
videoangiograms
were
recorded
with
a
scanning
laser
ophthalmoscope.
Volumetric
blood
flow
and
vascular
permeability
are
then
determined
using
MATLAB
in
accordance
with
the
mathema?cal
models
named
previously.
Diabetic
a)
b)
Diabetic
a)
b)
In
conclusion,
a
method
for
quan?ta?vely
mapping
volumetric
blood
flow
and
re?nal
permeability
using
fluorescein
videoangiography
is
proposed
as
an
alterna?ve,
noninvasive,
and
clinically
translatable
is
validated.
Since
fluorescein
is
FDA
approved
and
commonly
used
in
ophthalmology,
the
poten?al
for
expedited
clinical
applica?on
providing
early
indica?on
of
diabe?c
re?nopathy.
References
A
future
study
will
use
a
lesser
concentra?on
of
fluorescein
dye
to
alleviate
camera
satura?on,
16-‐bit
camera
to
increase
sensi?vity
in
local
changes
of
blood
flow,
modifica?on
to
mo?on
correc?on,
and
the
addi?on
of
user
interface
checking
modali?es
for
op?mal
data
selec?on.
Goals
include
the
replica?on
of
this
procedure
with
non-‐
saturated
videoangiography
data
to
produce
quan?fied
blood
flow
maps
and
extrac?on
frac?on
es?mates,
based
on
the
parameter,
E,
valida?ng
there
use
for
“sub-‐clinical”
biomarkers
for
diabe?c
re?nopathy.
[1]
K.M.
Tichauer,
M.
Guthrie,
L.
Hones,
L.
Sinha,
K.
St.
Lawrence,
J.J.
Kang-‐Mieler.
“Quan?ta?ve
re?nal
blood
flow
mapping
from
fluorescein
videoangiography
using
tracer
kine?c
modeling,”
Op?cs
LeRers,
vol.
40,
no.
10,
pp.
1–4.
[2]
K.
S.
St
Lawrence,
and
T.
Y.
Lee,
“An
adiaba?c
approxima?on
to
the
?ssue
homogeneity
model
for
water
exchange
in
the
brain:
II.
Experimental
valida?on,”
J
Cereb
Blood
Flow
Metab,
18(12),
1378-‐85
(1998).
Future
Work
&
Goals
Conclusion
Figure
1:
Demonstra?on
of
blood
flow
mapping
and
vascular
permiability
for
fluorescein
videoangiography
data
in
the
re?na
with
streptozotocin-‐induced
diabetes
Arterial
ROI
Venous
ROI
Tissue
ROI
Quan'ta've
Mapping
Selec'on
of
Regions
of
Interest