Doppler ultrasound uses high frequency sound waves to visualize blood vessels. It is a non-invasive technique to test for conditions like deep vein thrombosis. The document discusses the Doppler effect, which is a change in observed frequency of a wave caused by relative motion between the source and observer. It defines key terms like frequency and wavelength. It also describes different Doppler ultrasound techniques like continuous wave and color Doppler, and discusses applications in assessing blood flow velocity and direction in vessels.
Learn from our Slideshare about the differences between ultrasound transducers. We also cover tips on how to treat your probes and how to select the right one.
An overview of Doppler Effect in Ultrasonography - the medical imaging of the body using Ultrasound.
Includes Colour Doppler, Power Doppler, Spectral Doppler, Continuous Wave Doppler, Pulsed Wave Doppler, and comparisons with other Radiographic imaging modalities.
Learn from our Slideshare about the differences between ultrasound transducers. We also cover tips on how to treat your probes and how to select the right one.
An overview of Doppler Effect in Ultrasonography - the medical imaging of the body using Ultrasound.
Includes Colour Doppler, Power Doppler, Spectral Doppler, Continuous Wave Doppler, Pulsed Wave Doppler, and comparisons with other Radiographic imaging modalities.
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.
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.
This slide contain application of ultrasound and biological effects of ultrasound , ppt contains many GIF files and notes , which may not be accessible here ,,
A Strategic Approach: GenAI in EducationPeter Windle
Artificial Intelligence (AI) technologies such as Generative AI, Image Generators and Large Language Models have had a dramatic impact on teaching, learning and assessment over the past 18 months. The most immediate threat AI posed was to Academic Integrity with Higher Education Institutes (HEIs) focusing their efforts on combating the use of GenAI in assessment. Guidelines were developed for staff and students, policies put in place too. Innovative educators have forged paths in the use of Generative AI for teaching, learning and assessments leading to pockets of transformation springing up across HEIs, often with little or no top-down guidance, support or direction.
This Gasta posits a strategic approach to integrating AI into HEIs to prepare staff, students and the curriculum for an evolving world and workplace. We will highlight the advantages of working with these technologies beyond the realm of teaching, learning and assessment by considering prompt engineering skills, industry impact, curriculum changes, and the need for staff upskilling. In contrast, not engaging strategically with Generative AI poses risks, including falling behind peers, missed opportunities and failing to ensure our graduates remain employable. The rapid evolution of AI technologies necessitates a proactive and strategic approach if we are to remain relevant.
June 3, 2024 Anti-Semitism Letter Sent to MIT President Kornbluth and MIT Cor...Levi Shapiro
Letter from the Congress of the United States regarding Anti-Semitism sent June 3rd to MIT President Sally Kornbluth, MIT Corp Chair, Mark Gorenberg
Dear Dr. Kornbluth and Mr. Gorenberg,
The US House of Representatives is deeply concerned by ongoing and pervasive acts of antisemitic
harassment and intimidation at the Massachusetts Institute of Technology (MIT). Failing to act decisively to ensure a safe learning environment for all students would be a grave dereliction of your responsibilities as President of MIT and Chair of the MIT Corporation.
This Congress will not stand idly by and allow an environment hostile to Jewish students to persist. The House believes that your institution is in violation of Title VI of the Civil Rights Act, and the inability or
unwillingness to rectify this violation through action requires accountability.
Postsecondary education is a unique opportunity for students to learn and have their ideas and beliefs challenged. However, universities receiving hundreds of millions of federal funds annually have denied
students that opportunity and have been hijacked to become venues for the promotion of terrorism, antisemitic harassment and intimidation, unlawful encampments, and in some cases, assaults and riots.
The House of Representatives will not countenance the use of federal funds to indoctrinate students into hateful, antisemitic, anti-American supporters of terrorism. Investigations into campus antisemitism by the Committee on Education and the Workforce and the Committee on Ways and Means have been expanded into a Congress-wide probe across all relevant jurisdictions to address this national crisis. The undersigned Committees will conduct oversight into the use of federal funds at MIT and its learning environment under authorities granted to each Committee.
• The Committee on Education and the Workforce has been investigating your institution since December 7, 2023. The Committee has broad jurisdiction over postsecondary education, including its compliance with Title VI of the Civil Rights Act, campus safety concerns over disruptions to the learning environment, and the awarding of federal student aid under the Higher Education Act.
• The Committee on Oversight and Accountability is investigating the sources of funding and other support flowing to groups espousing pro-Hamas propaganda and engaged in antisemitic harassment and intimidation of students. The Committee on Oversight and Accountability is the principal oversight committee of the US House of Representatives and has broad authority to investigate “any matter” at “any time” under House Rule X.
• The Committee on Ways and Means has been investigating several universities since November 15, 2023, when the Committee held a hearing entitled From Ivory Towers to Dark Corners: Investigating the Nexus Between Antisemitism, Tax-Exempt Universities, and Terror Financing. The Committee followed the hearing with letters to those institutions on January 10, 202
Honest Reviews of Tim Han LMA Course Program.pptxtimhan337
Personal development courses are widely available today, with each one promising life-changing outcomes. Tim Han’s Life Mastery Achievers (LMA) Course has drawn a lot of interest. In addition to offering my frank assessment of Success Insider’s LMA Course, this piece examines the course’s effects via a variety of Tim Han LMA course reviews and Success Insider comments.
Operation “Blue Star” is the only event in the history of Independent India where the state went into war with its own people. Even after about 40 years it is not clear if it was culmination of states anger over people of the region, a political game of power or start of dictatorial chapter in the democratic setup.
The people of Punjab felt alienated from main stream due to denial of their just demands during a long democratic struggle since independence. As it happen all over the word, it led to militant struggle with great loss of lives of military, police and civilian personnel. Killing of Indira Gandhi and massacre of innocent Sikhs in Delhi and other India cities was also associated with this movement.
Acetabularia Information For Class 9 .docxvaibhavrinwa19
Acetabularia acetabulum is a single-celled green alga that in its vegetative state is morphologically differentiated into a basal rhizoid and an axially elongated stalk, which bears whorls of branching hairs. The single diploid nucleus resides in the rhizoid.
3. INTRODUCTION
The Doppler effect describes the change in the observed
frequency of a wave when there is relative motion between the
wave source and the observer. It was first proposed in 1842 by
Austrian mathematician and physicist Christian Johann Doppler.
To explain why the Doppler effect occurs, we need to start with a
few basic features of wave motion. Waves come in a variety of
forms: ripples on the surface of a pond, sounds (as with the siren),
light, and earthquake tremors all exhibit periodic wave motion.
3
4. DOPPLER EFFECT-KEY TERMS
FREQUENCY : This is the number of cycles that occurs in one second.
PERIOD: This is the amount of time required to complete one full cycle.
Period is mathematically related to frequency, wavelength, and wave
speed.
WAVELENGTH(λ) :The distance between a crest and the adjacent crest, or
the trough and an adjacent trough, of a wave. It is vector quantity. It is
measured in meter/seconds.
4
5. DOPPLER ULTRASOUND
Doppler ultrasound is a non invasive technique by which high
frequency sound waves are use to visualise blood vessels of the
body. Colour Doppler It is one of the main way to test for deep vein
thrombosis.
Deep Vein Thrombosis (DVT) is a condition where blood clots form
in veins deep in the body, usually in the leg. DVT can lead to more
serious problems, such as clot in the lungs. It can be life threatening.
5
7. TYPES OF DOPPLER ULTRASOND
Continuous waves
Duplex
Colour Doppler ultrasound
A continuous wave Doppler is a device that allows to
examine blood flow by implementing the Doppler effect. A
continuous wave Doppler is portable, easy to use and
cheap.
7
8. ADVANTAGES OF CONTINUOUS WAVE
DOPPLER
principles can be learned in a matter of minutes. Portable –
Continuous wave Doppler probes are often handheld. They basically
contain two piezoelectric crystals. One is for emitting a wave and the
other for receiving a reflected wave. There is also a speaker and/or a
small screen for signal interpretation.
Simple to use – A continuous Doppler is very simple to use.
8
9. DISADVANTAGES OF CONTINUOUS WAVE DOPPLER
No extra information – A continuous wave Doppler only offers
information about the blood flow. There is no anatomic information
available.
Sensitivity to operator mistakes – Because continuous wave Doppler
is qualitative an operator may not be aware of mistakes. For example,
a wrong or incorrect positioning
9
10. CONTINUOUS WAVE TRANSDUCER
The simplest Doppler systems use
continuous wave Doppler and are
usually small hand-held devices.
A continuous wave transducer of
two adjacent piezoelectric elements
angled slightly towards one
another. The transducer emits a
continuous sinusoidal wave in form
of (cos wt) and the receiver detects
echoes returning.
From the region of the overlap
between transmitter and receiver
10
11. DOPPLER SHIFT
(1) If blood if moving towards the
transducer then received
frequency will be greater than
the initial frequency.
(2) If blood is moving away from
the transducer then the received
frequency will be lower than the
initial frequency
The lower the Doppler angle, the
higher the Doppler shift.
11
12. DOPPLER FREQUENCY SHIFT EQUATION
ΔF=
𝑉2𝐹𝑂
𝐶
COSθ
ΔF is the Doppler frequency shift
F0 is the initial Doppler frequency
V is the velocity of moving blood
C is the speed of sound in tissue
Cosθ is the angle between the ultrasound beam and the flow
direction.
12
13. COLOUR DOPPLER ULTRASOUND
Colour Doppler ultrasound uses high frequency sound
waves to visualize the blood vessels and coloured images
of the blood vessels are obtained.
If there is a doubt of claudication, deep veins thrombosis,
to check the condition of blood supply to the foetus, colour
Doppler can be used.
13
16. HOW IS THIS TEST DONE?
A patient lies on a supine position, a sonographer applies
gel on the area of the body that is needed to be visualized.
This helps sound waves travel and give better results.
The sonographer will press the a transducer against the
area of interest.
16
17. COLOUR DUPLEX DOPPLER
Color duplex ultrasound is use to diagnosis vein problem
i.e. varicose vein.
We allow the sound wave to enter the leg where the picture
of the vein and blood flow is build up. We are looking at
where the superficial vein join the deep vein in the groin.
17
21. DOPPLER EFFECT EQUATIONS
V=Fλ--------------(1) V is the speed of sound in tissue
λ=
𝑉
𝐹
-----------------------(2) F is the frequency of sound in
air
F=
𝑉
λ
-----------------(3) λ is the wavelength of sound
21
24. DOPPLER EFFECT EQUATIONS
FOUR SCENAIRIOS OF DOPPLER EFFECT EQUATION
Scenario 1:when object moves towards the stationary source
of sound.
Vrel =vs+vo Fo=
𝑽 𝒔
+𝑽𝑶
𝑽 𝑺
*F
Fo =
𝑽 𝒔
+𝑽𝒐
λ
----------------(4)
Fo=
𝑽 𝑺
+𝑽𝑶
𝑽 𝑺/𝑭
24
25. DOPPLER EFFECT EQUATIONS
Scenario 2: When the observer moves away from the
stationary source of sound
Relative Velocity VREL=VS-VO
FO=
𝑽 𝑺−𝑽𝑶
λ
FO=
𝑽 𝑺
−𝑽𝑶
𝑽 𝑺
/𝑭
/
FO=
𝑽 𝑺
−𝑽𝑶
𝑽 𝑺
*F
25
26. DOPPLER EFFECT EQUATIONS
Scenario 3 : When source moving towards observer who is at
rest
Δλ=
𝑉 𝑆
𝑓
Δλ=VST since λ=
𝑣
𝑓
the observe frequency ϝ’
The wavelength observe is thus;
λ′=λ-Δλ λ′=λ-
𝑉 𝑆
𝐹
Since 𝐹′=
𝑉
λ′
, =
𝑉
λ−Δλ
=
𝑉
λ−(
𝑣
𝑓
)
=
𝑣
𝑣
𝑓
−(
𝑣 𝑠
𝑓
)
F’=
𝑉
𝑉−𝑉𝑆
∗ F
26
27. HEMODYNAMICS
The study of blood flow is called hemodynamics.
GENERAL PRINCIPLE OF CARDIOVASCULAR
SYSTEM
Velocity is the speed of movement with respect to time.
Flow is the volume of fluid with respect to time. Flow means how
much fluid flow through a pipe
Vcm/s =
𝑄 𝑚𝑙
/
𝑚
𝐴𝑐𝑚2 =
𝑓𝑙𝑜𝑤
𝑐𝑟𝑜𝑠𝑠 𝑠𝑒𝑐𝑡𝑖𝑜𝑛𝑎𝑙 𝑎𝑟𝑒𝑎
1meter = 39.37 inches
1millimeter = 1 cubic centimeter
1ml = 1cm3
27
29. HEMODYNAMICS(CONTD)
Velocity of the capillaries
Cross sectional area of the capillaries=3000cm2
Velocity=
5000𝑐𝑚3
/𝑚𝑖𝑛
3000𝑐𝑚2 = 1.6cm/min = 0.027cm/s
29
30. A GRAPH OF VELOCITY OF BLOOD FLOW
VERSUS BLOOD VESSELS
30
32. REFRENCES
1. Prof. M. A. Aweda. Principles of Doppler Imaging. Lagos University Teaching Hospital.
Lagos. 2012.
2.
J. T. Bushberg, et al. The Essential Physics of Medical Imaging. 2nd Ed. Philadelphia:
Lippincott Williams & Wilkins. 2002.
3. W. Huda, R. Sloan. Review of Radiologic Physics. 3rd ed. Philadelphia: Lippincott
Williams & Wilkins. 2009.
4. Adekunle, O. Akinyanju. Prevention of Stroke in Children with Sickle Cell Anaemia.
Sickle Cell Bulletin. Vol 8. No. 1. Sickle Cell Foundation Nigeria. 2017.
5. Siemens AG. Principles of Ultrasound Imaging. 1999: Med USSE
J. M. Adams. Ultrasound’s Transcranial Doppler Imaging Checks for Risk of Stroke.
2016. Cincinnati Children’s Hospital.
6. http://www.blog.cincinnatichildrens.org/radiology/
W. R. Hendee, E. R. Ritenour. Medical Imaging Physics. 4th Ed. New York: Wiley-Liss.
2002
32
But with quadrature detection, direction of flow is also possible.
where fo is the centre frequency and the bandwidth is the width of the frequency distribution.
Resolution is very low, due to use of high Q transducer.
Fourier Transform is used to construct an image.
Lack of TGC: Reflections created from RBC located at deeper depth will have a low amplitude than reflections from shallower depth.
This is determined by the depth of the range gate. The pulse travel time T determines the shortest possible time interval between two successive transmit pulses.
Using Shannon’s sampling theorem, the maximum unaliased frequency is as given above.
The PRF must be at least twice the sampling max Doppler freq shift.