Introduction to Sonography (RMI216) Lecture 10 PDF

RADIOLOGY PHYSICS& INSTRUMENTS (RMI216) Introduction to Sonography (LEC. 10) Dr. Mohammed Sayed Mohammed National Cancer Institute, Cairo University Faculty of Applied Health Sciences, Galala University. Qualified Expert of Radiologic Sciences, Ministry of Health, Egypt. Former Supervisor of Di...

RADIOLOGY PHYSICS& INSTRUMENTS (RMI216) Introduction to Sonography (LEC. 10) Dr. Mohammed Sayed Mohammed National Cancer Institute, Cairo University Faculty of Applied Health Sciences, Galala University. Qualified Expert of Radiologic Sciences, Ministry of Health, Egypt. Former Supervisor of Diagnostic Radiology Department, College of Applied Medical Sciences, University of Hail, KSA. Former STEM Ambassador, University of Reading, UK. What is sonography Sonography, or ultrasonography, is a diagnostic imaging technique using high-frequency sound waves to create images of internal body structures. Commonly used in medical fields such as obstetrics, cardiology, and musculoskeletal diagnostics. Non-invasive, real-time imaging method offering valuable insights into anatomy and pathology 2 Medical ultrasound is based on the use of high-frequency sound to aid in the diagnosis and treatment of patients. Ultrasound frequencies range from 2 to approximately 15 MHz, although even higher frequencies may be used in some situations. Physical Principles of Ultrasound The ultrasound beam originates from mechanical oscillations of numerous crystals in a transducer, which is excited by electrical pulses (piezoelectric effect). The transducer converts one type of energy into another (electrical mechanical/sound). 3 The ultrasound waves (pulses of sound) are sent from the transducer, propagate through different tissues, and then return to the transducer as reflected echoes. The returned echoes are converted back into electrical impulses by the transducer crystals and are further processed to form the ultrasound image presented on the screen. Ultrasound transducers contain a range of ultrasound frequencies, termed bandwidth. For example, 2.5-3.5 MHz for general abdominal imaging and 5.0-7.5 MHz for superficial imaging. Ultrasound waves are reflected at the surfaces between the tissues of different density, the reflection being proportional to the difference in impedance. If the difference in density is increased, the proportion of reflected sound is increased, and the proportion of 4 transmitted sound is proportionately decreased. If the difference in tissue density is very different, then the sound is completely reflected, resulting in total acoustic shadowing. Acoustic shadowing is present behind bones, calculi (stones in kidneys, gallbladder, etc.) and air (intestinal gas) (acoustic shadowing). Echoes are not produced if there is no difference in a tissue or between tissues. Homogenous fluids like blood, bile, urine, contents of simple cysts, ascites and pleural effusion are seen as echo-free structures. Interaction of Ultrasound Waves 1 with Tissue Ultrasound waves, when they strike a medium, cause expansion and compression of the medium. Ultrasound waves interact with tissue in four basic manners. Those interactions are: Reflection Scattering 5 Refraction Attenuation  How Does It Work? 1. A transducer emits high-frequency sound waves into the body. 2. Sound waves reflect off tissues and are detected by the transducer. 3. Reflected waves are converted into real-time images on a monitor. 6 4. Factors influencing the image: wave frequency, tissue density, and depth.  Applications of Sonography Diagnostic: Obstetrics (fetal development), cardiology (heart function), and internal organs. Therapeutic: Lithotripsy (kidney stones), HIFU High-Intensity Focused Ultrasound (HIFU) is a non-invasive medical procedure that is increasingly being used in 7 aesthetic medicine for skin tightening and facial rejuvenation. (tumor treatment). Emerging Uses: Drug delivery, bone growth stimulation Essential Tools and Settings Transducers: Linear for vascular work, curved for abdominal imaging. Adjustable Parameters: Frequency (high for detail, low for depth), depth, and gain settings. Importance of proper positioning and alignment to ensure accurate imaging. 8 Why Choose Sonography? Advantages: Non-invasive, radiation-free. Portable and cost-effective. Real-time imaging for dynamic assessments. 9 Limitations: Operator-dependent results. Limited penetration in obese patients or air-filled structures. Research and Future Directions Advances in 3D and 4D imaging technologies. Applications in veterinary medicine and materials science. Artificial intelligence integration for automated diagnosis 10 The Evolution of Sonography Discovery of Ultrasound: Inspired by SONAR technology in the 1940s. First Clinical Uses: Mid-20th century in cardiology and obstetrics. Advances: Transition from static 2D images to dynamic 3D/4D imaging. 11 Key Milestones: Ian Donald's work on fetal imaging (1958). Doppler ultrasound introduction in the 1970s 【 9 】【 10 】. Fundamentals of Ultrasound Physics Key Concepts: Frequency: Measured in MHz, higher frequencies = better resolution but less penetration. Wavelength and Speed: Sound speed varies by tissue type (bone > soft tissue > air). 12 Acoustic Impedance: Determines reflection and transmission of sound waves. Doppler Effect: Used to measure blood flow and heart function. Obstetric Sonography Early Pregnancy: Detect gestational sac and monitor fetal heart rate by 6 weeks. Fetal Development: Measure growth parameters (biparietal diameter, femur length). Other Uses: Amniotic fluid assessment, placental location, and anomaly detection 【 10 】. 13 Cardiac Ultrasound (Echocardiography) Techniques: Transthoracic echocardiogram (TTE). 14 Transesophageal echocardiogram (TEE). Uses: Assess heart valve function, detect clots, and evaluate heart muscle performance. Doppler Imaging: Measures blood flow velocities. Vascular Sonography Purpose: Identify blood clots, monitor arterial blockages, and assess vessel patency. Techniques: 15 Color Doppler: Visualizes flow direction and velocity. Power Doppler: Highlights slow-moving blood flow in smaller vessels. Ultrasound Safety Considerations Non-Ionizing Radiation: Safe for all patient populations, including pregnant women. Thermal Effects: Avoid excessive probe use in one area to minimize heating. 16 Mechanical Effects: Minimal risk when used appropriately. Regulations: Adherence to ALARA (As Low As Reasonably Achievable) principles. Challenges and Limitations Technical: Limited penetration in obese patients or air-filled organs like lungs. Operator Dependency: Image quality varies with sonographer expertise. 17 Artifact Issues: Reflection and refraction errors can distort images. Emerging Technologies AI Integration: Enhances diagnostic accuracy through automated analysis. Elastography: Measures tissue stiffness, useful in cancer detection. 18 Portable Devices: Expanding access to ultrasound in remote areas. Ultrasound Contrast Agents: Improving visualization of blood flow. Applications in Science and Industry Biological Research: Imaging small animal models, tissue engineering. Material Science: Non-destructive testing of materials. 19 Oceanography: SONAR-inspired techniques for underwater exploration. Clinical Case Studies Real-World Applications 1. Obstetric Case: Monitoring high-risk pregnancies. 20 2. Cardiac Case: Diagnosing congenital heart defects. 3. Vascular Case: Detecting deep vein thrombosis.  Summary and Applications. Sonography is a versatile tool with wide-ranging applications. Its non-invasive nature makes it indispensable in modern diagnostics. 21 Ongoing research continues to expand its potential. Takeaways from Sonography Sonography is a versatile and essential diagnostic tool. 22 Advances in technology continue to expand its applications. Operator skill and adherence to safety standards are crucial for optimal results. LECTURE OVERVIEW Objective: To familiarize with the Sonography.  THANK YOU Dr. Mohammed Sayed Mohammed National Cancer Institute, Cairo University Faculty of Applied Health Sciences, Galala University. Qualified Expert of Radiologic Sciences, Ministry of Health, 24 Egypt. Former Supervisor of Diagnostic Radiology Department, College of Applied Medical Sciences, University of Hail, KSA. Former STEM Ambassador, University of Reading, UK. [email protected] www.gu.edu.eg