1. Introduction to the Physics Echocardiography Introduction to the Physics Echocardiography Jose L. Rivera, M.D. January 9, 2010

2. The Basic Physics The Basic Physics Image Generation: The Physics of Ultrasound Doppler Imaging Modalities & Measurement of Blood Velocities Image Generation: The Physics of Ultrasound Doppler Imaging Modalities & Measurement of Blood Velocities Use of Calculus to manipulate ultrasound Doppler information Use of Calculus to manipulate ultrasound Doppler information

3. Objectives Explain how the various modes of ultrasound image are generated Explain how the various modes of ultrasound image are generated Define the basic physics and calculus concepts used in medical ultrasound imaging Define the basic physics and calculus concepts used in medical ultrasound imaging

4. Objectives Discuss the utility and applications of Doppler color flows imaging. Discuss the utility and applications of Doppler color flows imaging. Explain the difference between Pulsed Doppler and Continuous Doppler and their applications Explain the difference between Pulsed Doppler and Continuous Doppler and their applications

5. Physics of Echocardiography Brief Review of Echocardiography Physics to: Understand the generation, propagation and detection of Ultrasounds Waves Explain how the physical principles affect our measurements and images Appreciate the strengths and limitations of the technology

6. THE BASIC PHYSICS ULTRASOUND WAVES IN A FLUID BEHAVE LIKE ELECTROMAGNETIC WAVES IN A VACUUM ULTRASOUND WAVES IN A FLUID BEHAVE LIKE ELECTROMAGNETIC WAVES IN A VACUUM THEIR ENERGY SOURCE ORIGINATES FROM ELECTROMAGNETIC WAVES & THEY RETAIN SOME OF THOSE WAVE PROPERTIES THEIR ENERGY SOURCE ORIGINATES FROM ELECTROMAGNETIC WAVES & THEY RETAIN SOME OF THOSE WAVE PROPERTIES THEIR PROPERTIES CAN BE ANALYZED WITH BASIC CALCULUS (Integral & Differential) THEIR PROPERTIES CAN BE ANALYZED WITH BASIC CALCULUS (Integral & Differential)

7. The following diagrams on the following slides were obtained from Sidebotham’s “Perioperative Transesophageal Echocardiography The following diagrams on the following slides were obtained from Sidebotham’s “Perioperative Transesophageal Echocardiography

8. Piezoelectric Effect

9. Piezoelectric effect results in Compression & Rarefaction: The Shockwave

10. Damping Material is used to “ring down” the Pulse Length & Bandwidth which results in improved resolution

11. Ultrasound Interactions with Tissue Interfaces Arrow represent Vectors whose length equal the strength & direction of the reflected signal A and B represent specular (mirror like) reflectors, the B return signal does not return to the transducer C and D have a rough surface that is typical of human tissue E are objects smaller than a wavelength & therefore scatter the energy

12. Interactions of Ultrasound Waves with Tissue The interactions will determine the types of images & artifacts that are generated

13. Reflection, Attenuation & Time Gain Conpensation Settings

14. Transducer Frequency & Wavelength affect Resolution & Penetration

15. TRANSDUCERS DESIGN Piezoelectric Principle is universal Linear Array Nerve Block probe Mechanical Sector Scan old Site Rite Phase Array Design 3D probes

16. Mechanical Sector Scan

17. PHASE ARRAY TRANSDUCER Generating the Summation Wave front

18. Steering the Phase Array Summation Wave Front

19. 3D probes

20. Types of Ultrasound “Formats” A mode (amplitude) B mode (brightness) Most common M mode (motion) Doppler Pulse Wave Continuous Wave Color Flow 3D

21. A Mode (amplitude) B Mode (2D) M Mode (motion)

22. 3D Format Fig 3.48 video.avi

23. SUMMARY Understanding Echocardiography Physics will enhance our understanding of: The physical principles that affect our measurements and images Knowing when to believe or doubt our results The strengths and limitations of the technology