Lab 1 - Introduction to Ultrasound PDF

Radiography & Medical Imaging Science ( Ultrasound Imaging ) Lecture 1 Introduction to Ultrasound Course: FRD3061Medical Imaging Science and Methods 2-Ultrasound 1 Lecture : Basic Scanning Principles Definition Ultrasound: • is the term used to describe sound of frequencies above 20 000 Hertz (Hz...

Radiography & Medical Imaging Science ( Ultrasound Imaging ) Lecture 1 Introduction to Ultrasound Course: FRD3061Medical Imaging Science and Methods 2-Ultrasound 1 Lecture : Basic Scanning Principles Definition Ultrasound: • is the term used to describe sound of frequencies above 20 000 Hertz (Hz), beyond the range of human hearing. Frequencies of 1–30 megahertz (MHz) are typical for diagnostic ultrasound. • Diagnostic ultrasound imaging depends on the computerized analysis of reflected ultrasound waves, which non-invasively build up fine images of internal body structures. Ultrasound Probes • Different ranges of frequency are used for examination of different parts of the body: • 2–5 MHz for abdominal areas • 5–10 MHz for small and superficial parts • 1–5 MHz for the thorax area. Ultrasound probe from INSIDE: Backing element Designed to direct energy out the front of the transducer and eliminate energy loss from the backside of the piezoelectric elements. Piezoelectric crystals Ceramic crystals used to send and receive sound waves. Acoustic matching layer Improve and increase the energy transmitting efficiency. Acoustic lens Used to focus the ultrasound beam at the target distance How does the transducer probes work? When an electric current is applied to these crystals, causes it to vibrate and producing a mechanical sound waves that travel outward. Conversely, when the mechanical sound waves hit the crystals, they emit electrical currents. Therefore, the same crystals can be used to send and receive sound waves. Ultrasound and Resolution • The resolution attainable is higher with shorter wavelengths, with the wavelength being inversely proportional to the frequency. However, the use of high frequencies is limited by their greater attenuation (loss of signal strength) in tissue and thus shorter depth of penetration. Attenuation • As sound waves travel through tissue, there is a progressive reduction in the intensity of the wave. This process is known as attenuation. • Higher frequency sound waves = more attenuation • lower frequency sound waves = Less attenuation • The attenuation occurs as a result of four processes: reflection, refraction, scattering and absorption. • Ultrasound IMAGE Indicator (Orientation Marker) Position • In general, for almost all standard applications and procedures the indicator orientation marker position will be on the LEFT side of the screen. In cardiac mode, the indicator orientation marker will be on the RIGHT side of the screen. Ultrasound techniques • Doppler ultrasound is a noninvasive test that can be used to estimate the blood flow through your blood vessels by bouncing high-frequency sound waves (ultrasound) off circulating red blood cells. • Color Doppler (CD): imaging displays the average blood velocity in a vessel, based on the mean Doppler frequency shift of the scatterers (the blood cells). • Power Doppler (PD, also known as color Doppler energy or ultrasound angiography: In general, it is up to five times more sensitive in detecting blood flow than color Doppler, being more sensitive to slow blood flow in small vessels; however, it gives no information about the direction of flow. Color Doppler Color Doppler Power Doppler Power Doppler ULTRASOUND MACHINE Benefits of Using Ultrasound Gel • acts as a conductive medium by reducing air space between the patient’s skin and the ultrasound transducer, • To reduce acoustic impedance and reflection to allow for a clear image to be produced. • Types of Ultrasound gel: • 1- oil-based ultrasound gels • 2- water-soluble ultrasound gel Adverse effects • There is no Adervse effects investgated in the clinical enviroment, but there is according to the theroatical part: • The kinetic energy of ultrasound waves can cause adverse effects in tissue. Non-thermal effects include cavitation, direct mechanical damage to cells by acceleration, movement of particles in fluid (acoustic streaming) and aggregation of particles or cells. • Cavitation is the formation of voids, or bubbles, in a biological structure during the rarefaction phase of a sound wave. These bubbles may grow with changes in pressure or collapse during the positive pressure phase. The risk of cavitation is low at the ultrasound intensities used in medical diagnosis. Furthermore, diagnostic ultrasound is applied in very short pulses. Patient Preparation Pre and Post Start the Ultrasound Scanning • Check the Patient name, ID and DOB. • Check the patient history and pervious images if applicable. • Ask the patient about their health problem and where is the pain. • Check if the patient followed the pre-examination preparation instructions (fasting 8 hours, full bladder ect…). • Explain the full procedure and breath instruction to the patient. • Cover the patient body except the ROI. • Let the patient move toward you and the machine, and make sure that the patient is in comfort position. • Adjust your chair height with the ultrasound machine and in patient bed. • Make sure to use warm gel and assist the patient to clean the gel after end of the procedure. Scanning Planes Interpreted: Sagittal Scanning Plane (Longitudinal) Scanning Planes Interpreted: Sagittal Scanning Plane (Longitudinal) Liver: Sagittal Plane Kidney: Sagittal Plane Carotid: Sagittal Plane Kideny: Sagittal Plane Gallbladder: Sagittal Plane Spleen: Sagittal Plane Scanning Planes Interpreted: Coronal Plane Scanning Planes Interpreted: Transverse Plane Scanning Planes Interpreted: Transverse Plane Scanning Planes Interpreted: Transverse Plane Scanning Planes Interpreted: Transverse Plane Kidney: Transverse Plane Liver: Transverse Plane Gallbladder : Transverse Plane Spleen: Transverse Plane Carotid: Transverse Plane Thyroid: Transverse Plane References ➢Bates, J.A., (2011) Abdominal Ultrasound: How, Why and When, Churchill Livingstone. ➢Gill R. (2016) the physics and technology of diagnostic ultrasound. High Frequency Publishing, Melbourne. ➢Kremkau, F.W. (2016), Sonography Principles and Instruments, 9th Ed, Saunders Elsevier, Missouri, USA. ➢Rumack, C.M., Wilson S.R., Charboneau, J.W., (2011), Diagnostic Ultrasound Vol 1 & 2. 4th Edition, Mosby. ➢Curry R, Tempkin BB, 2016 Sonography: an introduction to normal structure and functional anatomy, 4th Ed. Elsevier Saunders St Louis Mo. ➢Tempkin BB, 2014 Ultrasound Scanning Principles and Protocols, 4thEd. Elsevier Saunders, St Louis Mo. THANKS FOR LISTENING