1. Perfusion MRI uses specific sequences to generate maps of blood perfusion parameters like blood volume, blood flow, mean transit time, and time to peak in tissues.
2. Diffusion MRI uses diffusion sensitizing gradients to map the diffusion of water molecules in tissues, revealing microscopic details of tissue architecture.
3. Both techniques provide clinically useful information when combined with other MRI sequences. Perfusion and diffusion MRI are important in evaluating acute brain ischemia like strokes to distinguish salvageable tissue.
Everything regarding the physics of MRA is given along with flow charts and images. Also have covered new advances and refrences taken from MR made easy and some articles related to MRI
Everything regarding the physics of MRA is given along with flow charts and images. Also have covered new advances and refrences taken from MR made easy and some articles related to MRI
Magnetic Resonance Angiography and VenographyAnjan Dangal
Introduction to MR Angiography and Venography Procedure of Brain . Includes Indication, MRI protocol, planning and anatomy as well as brief intoduction to physics behind MRA and MRV principle.
Its important to recognise the myelination pattern in neonates and infants. This presentation talks about the myelination pattern and imaging of white matter diseases in children.
Magnetic Resonance Angiography and VenographyAnjan Dangal
Introduction to MR Angiography and Venography Procedure of Brain . Includes Indication, MRI protocol, planning and anatomy as well as brief intoduction to physics behind MRA and MRV principle.
Its important to recognise the myelination pattern in neonates and infants. This presentation talks about the myelination pattern and imaging of white matter diseases in children.
Demonstrate how to do and use chest ultrasound for diagnosis and management of different pulmonary and pleural diseases also for taken.lung biopsy and insertion of central venous line differential diagnosis of interstetial lung disease .pleural biopsy and diaphragmatic movement .vascular abnormality cardic disease and oericardial effusion
Ultrasound Physics Made easy - By Dr Chandni WadhwaniChandni Wadhwani
History of ultrasound, Principle of Ultrasound.
Ultrasound wave and its interactions
Ultrasound machine and its parts, Image display, Artifacts and their clinical importance
what is Doppler ultrasound, Elastography and Recent advances in field of ultrasound.
Safety issues in ultrasound.
GDG Cloud Southlake #33: Boule & Rebala: Effective AppSec in SDLC using Deplo...James Anderson
Effective Application Security in Software Delivery lifecycle using Deployment Firewall and DBOM
The modern software delivery process (or the CI/CD process) includes many tools, distributed teams, open-source code, and cloud platforms. Constant focus on speed to release software to market, along with the traditional slow and manual security checks has caused gaps in continuous security as an important piece in the software supply chain. Today organizations feel more susceptible to external and internal cyber threats due to the vast attack surface in their applications supply chain and the lack of end-to-end governance and risk management.
The software team must secure its software delivery process to avoid vulnerability and security breaches. This needs to be achieved with existing tool chains and without extensive rework of the delivery processes. This talk will present strategies and techniques for providing visibility into the true risk of the existing vulnerabilities, preventing the introduction of security issues in the software, resolving vulnerabilities in production environments quickly, and capturing the deployment bill of materials (DBOM).
Speakers:
Bob Boule
Robert Boule is a technology enthusiast with PASSION for technology and making things work along with a knack for helping others understand how things work. He comes with around 20 years of solution engineering experience in application security, software continuous delivery, and SaaS platforms. He is known for his dynamic presentations in CI/CD and application security integrated in software delivery lifecycle.
Gopinath Rebala
Gopinath Rebala is the CTO of OpsMx, where he has overall responsibility for the machine learning and data processing architectures for Secure Software Delivery. Gopi also has a strong connection with our customers, leading design and architecture for strategic implementations. Gopi is a frequent speaker and well-known leader in continuous delivery and integrating security into software delivery.
Connector Corner: Automate dynamic content and events by pushing a buttonDianaGray10
Here is something new! In our next Connector Corner webinar, we will demonstrate how you can use a single workflow to:
Create a campaign using Mailchimp with merge tags/fields
Send an interactive Slack channel message (using buttons)
Have the message received by managers and peers along with a test email for review
But there’s more:
In a second workflow supporting the same use case, you’ll see:
Your campaign sent to target colleagues for approval
If the “Approve” button is clicked, a Jira/Zendesk ticket is created for the marketing design team
But—if the “Reject” button is pushed, colleagues will be alerted via Slack message
Join us to learn more about this new, human-in-the-loop capability, brought to you by Integration Service connectors.
And...
Speakers:
Akshay Agnihotri, Product Manager
Charlie Greenberg, Host
Accelerate your Kubernetes clusters with Varnish CachingThijs Feryn
A presentation about the usage and availability of Varnish on Kubernetes. This talk explores the capabilities of Varnish caching and shows how to use the Varnish Helm chart to deploy it to Kubernetes.
This presentation was delivered at K8SUG Singapore. See https://feryn.eu/presentations/accelerate-your-kubernetes-clusters-with-varnish-caching-k8sug-singapore-28-2024 for more details.
The Art of the Pitch: WordPress Relationships and SalesLaura Byrne
Clients don’t know what they don’t know. What web solutions are right for them? How does WordPress come into the picture? How do you make sure you understand scope and timeline? What do you do if sometime changes?
All these questions and more will be explored as we talk about matching clients’ needs with what your agency offers without pulling teeth or pulling your hair out. Practical tips, and strategies for successful relationship building that leads to closing the deal.
GraphRAG is All You need? LLM & Knowledge GraphGuy Korland
Guy Korland, CEO and Co-founder of FalkorDB, will review two articles on the integration of language models with knowledge graphs.
1. Unifying Large Language Models and Knowledge Graphs: A Roadmap.
https://arxiv.org/abs/2306.08302
2. Microsoft Research's GraphRAG paper and a review paper on various uses of knowledge graphs:
https://www.microsoft.com/en-us/research/blog/graphrag-unlocking-llm-discovery-on-narrative-private-data/
Transcript: Selling digital books in 2024: Insights from industry leaders - T...BookNet Canada
The publishing industry has been selling digital audiobooks and ebooks for over a decade and has found its groove. What’s changed? What has stayed the same? Where do we go from here? Join a group of leading sales peers from across the industry for a conversation about the lessons learned since the popularization of digital books, best practices, digital book supply chain management, and more.
Link to video recording: https://bnctechforum.ca/sessions/selling-digital-books-in-2024-insights-from-industry-leaders/
Presented by BookNet Canada on May 28, 2024, with support from the Department of Canadian Heritage.
Neuro-symbolic is not enough, we need neuro-*semantic*Frank van Harmelen
Neuro-symbolic (NeSy) AI is on the rise. However, simply machine learning on just any symbolic structure is not sufficient to really harvest the gains of NeSy. These will only be gained when the symbolic structures have an actual semantics. I give an operational definition of semantics as “predictable inference”.
All of this illustrated with link prediction over knowledge graphs, but the argument is general.
PHP Frameworks: I want to break free (IPC Berlin 2024)Ralf Eggert
In this presentation, we examine the challenges and limitations of relying too heavily on PHP frameworks in web development. We discuss the history of PHP and its frameworks to understand how this dependence has evolved. The focus will be on providing concrete tips and strategies to reduce reliance on these frameworks, based on real-world examples and practical considerations. The goal is to equip developers with the skills and knowledge to create more flexible and future-proof web applications. We'll explore the importance of maintaining autonomy in a rapidly changing tech landscape and how to make informed decisions in PHP development.
This talk is aimed at encouraging a more independent approach to using PHP frameworks, moving towards a more flexible and future-proof approach to PHP development.
DevOps and Testing slides at DASA ConnectKari Kakkonen
My and Rik Marselis slides at 30.5.2024 DASA Connect conference. We discuss about what is testing, then what is agile testing and finally what is Testing in DevOps. Finally we had lovely workshop with the participants trying to find out different ways to think about quality and testing in different parts of the DevOps infinity loop.
2. PERFUSION
Perfusion is the passage of fluid through the circulatory system or lymphatic system to
an organ or a tissue, usually referring to the delivery of blood to a capillary bed in
tissue. Perfusion is measured as the rate at which blood is delivered to tissue, or volume
of blood per unit time (blood flow) per unit tissue mass. The SI unit is m3/(s·kg),
although for human organs perfusion is typically reported in ml/min/g.
3. The word is derived from the French verb "perfuser" meaning to "pour over or
through". All animal tissues require an adequate blood supply
for health and life. Poor perfusion (malperfusion), that is, ischemia, causes
health problems, as seen in cardiovascular disease, including coronary artery
disease, cerebrovascular disease, peripheral artery disease, and many other
conditions.
PERFUSION
4. DISCOVERY
In 1920, August Krogh was awarded the Nobel Prize in Physiology or
Medicine for his discovering the mechanism of regulation
of capillaries in skeletal muscle. Krogh was the first to describe the adaptation
of blood perfusion in muscle and other organs according to demands through
the opening and closing of arterioles and capillaries.
5. PERFUSION MRI
Perfusion MRI or perfusion-weighted imaging (PWI) is perfusion scanning by
the use of a particular MRI sequence. The acquired data are then post
processed to obtain perfusion maps with different parameters, such as BV
(blood volume), BF (blood flow), MTT (mean transit time) and TTP (time to
peak).
6. CLINICAL USE
In cerebral infarction, the penumbra has decreased perfusion. Another MRI
sequence, diffusion weighted MRI, estimates the amount of tissue that is
already necrotic, and the combination of those sequences can therefore be used
to estimate the amount of brain tissue that is salvageable
by thrombolysis and/or thrombectomy.
7. SEQUENCES
There are 3 main techniques for perfusion MRI:
Dynamic susceptibility contrast (DSC): Gadolinium contrast is
injected, and rapid repeated imaging (generally gradient-echo echo-
planar T2 weighted) quantifies susceptibility-induced signal loss.
Dynamic contrast enhanced (DCE): Measuring shortening of
the spin–lattice relaxation(T1) induced by a gadolinium contras bolus
Arterial spin labeling (ASL): Magnetic labeling of arterial blood
below the imaging slab, without the need of gadolinium contrast
8. DYNAMIC SUSCEPTIBILITY CONTRAST
In Dynamic susceptibility contrast MR imaging (DSC-MRI,
or simply DSC), Gadolinium contrast agent (Gd) is injected
(usually intravenously) and a time series of fast T2*-
weighted images is acquired.
9. DYNAMIC CONTRAST-ENHANCED IMAGING
Dynamic contrast-enhanced (DCE) imaging gives information about
physiological tissue characteristics. For example, it enables analysis of blood
vessels generated by a brain tumor. The contrast agent is blocked by the
regular blood–brain barrier but not in the blood vessels generated by the
tumor. The concentration of the contrast agent is measured as it passes from
the blood vessels to the extracellular space of the tissue (it does not pass the
membranes of cells) and as it goes back to the blood vessels.
10. The contrast agents used for DCE-MRI are often gadolinium based. Interaction with the
gadolinium (Gd) contrast agent causes the relaxation time of water protons to decrease, and
therefore images acquired after gadolinium injection display higher signal in T1-weighted
images indicating the present of the agent. It is important to note that, unlike some
techniques such as PET imaging, the contrast agent is not imaged directly, but by an indirect
effect on water protons.
DYNAMIC CONTRAST-ENHANCED IMAGING
11. ARTERIAL SPIN LABELING
Arterial spin labeling (ASL) has the advantage of not relying on an
injected contrast agent, instead inferring perfusion from a drop in signal
observed in the imaging slice arising from inflowing spins (outside the
imaging slice) having been selectively saturated.
12. DIFFUSION
Diffusion is the movement of a substance from an area of high concentration to
an area of low concentration.
Diffusion happens in liquids and gases because their particles move randomly from
place to place.
Diffusion is an important process for living things; it is how substances move in and
out of cells.
13. WHAT CAUSES DIFFUSION?
In gases and liquids, particles move randomly from place to place. The particles
collide with each other or with their container. This makes them change direction.
Eventually, the particles are spread through the whole container.
Diffusion happens on its own, without stirring, shaking or wafting.
14. WHY IS DIFFUSION USEFUL?
In living things, substances move in and out of cells by diffusion. For example:
Respiration produces waste carbon dioxide, causing the amount of carbon dioxide to
increase in the cell. Eventually, the carbon dioxide concentration in the cell is higher
than that in the surrounding blood. The carbon dioxide then diffuses out through the
cell membrane and into the blood.
15. Water diffuses into plants through their root hair cells. The water moves
from an area of high concentration (in the soil) to an area of lower
concentration (in the root hair cell). This is because root hair cells
are partially permeable. The diffusion of water like this, is called osmosis.
WHY IS DIFFUSION USEFUL?
16. DIFFUSION MRI
Diffusion-weighted magnetic resonance imaging (DWI or DW-MRI) is the use
of specific MRI sequences as well as software that generates images from the
resulting data that uses the diffusion of water molecules to generate contrast in
MR images.
17. It allows the mapping of the diffusion process of molecules, mainly water,
in biological tissues, in vivo and non-invasively. Molecular diffusion in tissues
is not free, but reflects interactions with many obstacles, such
as macromolecules, fibers, and membranes.
DIFFUSION MRI
18. Water molecule diffusion patterns can therefore reveal microscopic details about tissue
architecture, either normal or in a diseased state. A special kind of DWI, diffusion
tensor imaging (DTI), has been used extensively to map white matter tractography in
the brain.
DIFFUSION MRI
19. TECHNICAL EVOLUTION OF DIFFUSION WEIGHTED
IMAGING
The goal of all imaging procedures is generation of an image contrast with a good
spatial resolution. Initial evolution of diagnostic imaging focused on tissue density
function for signal contrast generation. In 1970s, the work of Lauterbur PC, Mansfield
P and Ernst R, modern clinical MRI came into the field of medicine. MRI provided an
excellent contrast resolution not only from tissue (proton) density, but also from tissue
relaxation properties.
20. After initial focus on T1 and T2 relaxation properties researchers explored other
methods to generate contrast exploiting other properties of water molecules. Diffusion
weighted imaging (DWI) was a result of such efforts by researchers like Stejskal,
Tanner and Le Bihan.
TECHNICAL EVOLUTION OF DIFFUSION WEIGHTED
IMAGING
21. In 1984, before MRI contrast became available, Denis Le Bihan, tried to differentiate
liver tumors from angiomass. He hypothesized that a molecular diffusion measurement
would result in low values for solid tumors, because of restriction of molecular
movement. Based on the pioneering work of Stejskal and Tanner in the 1960s, he
thought that diffusion encoding could be accomplished using specific magnetic
gradient pulses.
TECHNICAL EVOLUTION OF DIFFUSION WEIGHTED
IMAGING
22. It was a challenging task to integrate the diffusion encoding gradients in to the
conventional sequences and initial experience in the liver with a 0.5T scanner was very
disappointing. Firstly diffusion MRI was a very slow method and it was very sensitive
to motion artifacts due to respiration.
TECHNICAL EVOLUTION OF DIFFUSION WEIGHTED
IMAGING
23. It was not until the availability of Echo-Planar Imaging (EPI) in the early 1990s, that
DWI could become a reality in the field of clinical imaging. EPI based diffusion
sequences were fast and solved the problems of motion artifacts. Early work by
Moseley et al and Warach et al established DWI as a cornerstone for early detection of
acute stroke.
TECHNICAL EVOLUTION OF DIFFUSION WEIGHTED
IMAGING
24. In a DWI sequence diffusion sensitization gradients are applied on either side of the
180° refocusing pulse. The parameter “b value” decides the diffusion weighting and is
expressed in s/mm2. It is proportional to the square of the amplitude and duration of
the gradient applied. Diffusion is qualitatively evaluated on trace images and
quantitatively by the parameter called apparent diffusion coefficient (ADC). Tissues
with restricted diffusion are bright on the trace image and hypointense on the ADC
map.
TECHNICAL EVOLUTION OF DIFFUSION WEIGHTED
IMAGING
25. CLINICAL APPLICATIONS OF DWI
Acute brain ischemia:
Ever since its inception acute brain ischemia has been the most
successful application of DWI . Diffusion MRI today is the imaging
modality of choice for stroke patients. The use of DWI in combination
with perfusion MRI, which outlines salvageable areas of ischemia and
MR angiography, provides a useful guide for stroke management.
26. Acute infarct. Axial FLAIR image (A) shows geographic hyper intensity involving right parieto-
occipital region and basal ganglia. Diffusion weighted imaging shows restricted diffusion with
high signal image (B) and low signal intensity on apparent diffusion coefficient map (C).