Principle of Ultrasound.pptx

Ultrasound is a non-invasive medical imaging modality widely used in various clinical applications.
It is based on the principle of using high-frequency sound waves to create real-time images of internal structures within the human body.
In this presentation, we will discuss into the fundamental principles of ultrasound imaging and its applications in radiology.

1. Principle of Medical Ultrasound Imaging Presenter : Dr. Dheeraj Kumar MRIT, Ph.D. (Radiology and Imaging) Assistant Professor Medical Radiology and Imaging Technology School of Health Sciences, CSJM University, Kanpur

2. Introduction Ultrasound is a non-invasive medical imaging modality widely used in various clinical applications. It is based on the principle of using high-frequency sound waves to create real-time images of internal structures within the human body. In this presentation, we will discuss into the fundamental principles of ultrasound imaging and its applications in radiology. 03-08-2023 Principle of Medical Ultrasound Imaging By- Dheeraj Kumar 2

3. Basics of Ultrasound Ultrasound Definition: Ultrasound, also known as sonography, is a diagnostic imaging technique that utilizes high-frequency sound waves (typically between 2 to 18 MHz) to visualize internal organs and soft tissues. How Ultrasound Works: During an ultrasound exam, a transducer is placed on the skin's surface and emits sound waves into the body. Reflection of Sound Waves: These sound waves encounter different tissue boundaries within the body and are reflected back to the transducer. Transducer Function: The transducer both emits and receives sound waves, acting as a sender and receiver of ultrasound signals. 03-08-2023 Principle of Medical Ultrasound Imaging By- Dheeraj Kumar 3

4. The Piezoelectric Effect Piezoelectric Crystals: Ultrasound transducers are equipped with piezoelectric crystals made of materials like ceramics or polymers. The Piezoelectric Effect: When an electric voltage is applied to the piezoelectric crystals, they change shape or vibrate at a specific frequency, generating ultrasound waves. Receiving Sound Waves: When sound waves return to the transducer after reflection from internal structures, the piezoelectric crystals convert these sound waves back into electrical signals. 03-08-2023 Principle of Medical Ultrasound Imaging By- Dheeraj Kumar 4

5. Sound Wave Propagation Speed of Sound: The speed of sound in human tissues is approximately 1540 m/s (meters per second). However, it may vary slightly depending on tissue density and elasticity. Attenuation: As ultrasound waves pass through tissues, they lose energy due to absorption and scattering, leading to reduced signal strength and image quality. A-mode (Amplitude Mode): A-mode ultrasound displays the amplitude (strength) of reflected echoes as vertical spikes. It was one of the earliest display formats used in ultrasound. 03-08-2023 Principle of Medical Ultrasound Imaging By- Dheeraj Kumar 5

6. Pulse-Echo Technique Pulse-Echo Technique: The pulse-echo technique is the foundation of most medical ultrasound imaging. Transmitting and Receiving Pulses: The transducer operates in a pulsed mode, where it alternates between transmitting short bursts (pulses) of ultrasound waves into the body and receiving the reflected echoes. Time-of-Flight Measurement: The time taken for sound waves to travel to and from tissue interfaces is measured, allowing the ultrasound system to calculate tissue depth. 03-08-2023 Principle of Medical Ultrasound Imaging By- Dheeraj Kumar 6

7. Ultrasound Image Formation Image Reconstruction: After receiving the reflected echoes, the ultrasound system processes and reconstructs the data to create a 2D image of the internal structures. Beamforming: Beamforming is a technique used to electronically focus the ultrasound beam. By adjusting the timing of sound wave emissions from multiple transducer elements, the system can concentrate the ultrasound waves at a specific depth, improving image resolution and quality. Scanning Modes: Two widely used scanning modes are B-mode (Brightness Mode) and M-mode (Motion Mode). B-mode displays grayscale images representing tissue density, while M-mode displays moving structures, such as heart valves, over time. 03-08-2023 Principle of Medical Ultrasound Imaging By- Dheeraj Kumar 7

8. Doppler Ultrasound Doppler Effect: Doppler ultrasound is a specialized technique that utilizes the Doppler effect to assess blood flow within the body. Color Doppler: In color Doppler imaging, blood flow is represented using colors to indicate the direction and speed of blood flow. This is especially useful in evaluating blood flow patterns in vessels and identifying areas of turbulence or blockage. Spectral Doppler: Spectral Doppler provides a graphical representation of blood flow velocity over time. This waveform can be used to analyze blood flow characteristics and diagnose conditions like arterial stenosis or valve regurgitation. 03-08-2023 Principle of Medical Ultrasound Imaging By- Dheeraj Kumar 8

9. Ultrasound Applications in Radiology Abdominal Ultrasound: Abdominal ultrasound is commonly used to visualize organs such as the liver, kidneys, gallbladder, pancreas, and spleen. It aids in diagnosing conditions like gallstones, liver masses, and kidney abnormalities. Obstetric Ultrasound: Obstetric ultrasound is used during pregnancy to monitor fetal development, assess the placenta, and detect any potential abnormalities. Musculoskeletal Ultrasound: Musculoskeletal ultrasound is valuable in evaluating joints, tendons, muscles, and soft tissue masses, aiding in the diagnosis of conditions like tendonitis, ligament tears, and joint effusions. Cardiac Ultrasound (Echocardiography): Echocardiography is an essential tool for assessing the structure and function of the heart, including heart valves, chambers, and blood flow patterns. 03-08-2023 Principle of Medical Ultrasound Imaging By- Dheeraj Kumar 9

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11. Advantages Non-invasive and Safe: Ultrasound imaging does not involve ionizing radiation, making it safe for patients and operators. Real-time Imaging: Ultrasound provides immediate, real-time images, allowing for dynamic evaluation of structures and functions. Versatility: Ultrasound is applicable to a wide range of medical specialties, providing valuable diagnostic information . 03-08-2023 Principle of Medical Ultrasound Imaging By- Dheeraj Kumar 11

12. Limitations Limited Penetration: Ultrasound has limited penetration through bone and gas-filled structures, restricting its use in certain regions of the body. Operator Dependency: Image quality can be influenced by the operator's skill and experience in positioning and acquiring images. 03-08-2023 Principle of Medical Ultrasound Imaging By- Dheeraj Kumar 12

13. Conclusion U ltrasound imaging is a valuable and versatile diagnostic tool in radiology. Understanding the principles of ultrasound, including the pulse-echo technique and Doppler imaging, is essential for radiology students to become competent practitioners. With its non-invasive nature, real-time capabilities, and wide range of applications, ultrasound continues to play a significant role in the field of medical imaging. Thank you for your attention, and we hope this presentation has provided a clear understanding of the principle of medical ultrasound imaging. 03-08-2023 Principle of Medical Ultrasound Imaging By- Dheeraj Kumar 13

14. References Diagnostic Ultrasound: Principles, Instruments, and Exercises" by K. Thomas Varghese Jr., Robin L. Smith, and Thomas L. Szabo. "Introduction to Medical Imaging: Physics, Engineering, and Clinical Applications" by Nadine Barrie Smith and Andrew Webb. "The Physics of Diagnostic Imaging" by Philip W. Ballinger and David J. Dowsett . "Ultrasound Physics and Instrumentation" by Wayne R. Hedrick and David L. Smith. 03-08-2023 Principle of Medical Ultrasound Imaging By- Dheeraj Kumar 14

15. THANK YOU 03-08-2023 Principle of Medical Ultrasound Imaging By- Dheeraj Kumar 15