Ultrasounds: Introduction, Types, and Applications PDF

ULTASOUND INTRODUCTION Sound: Is a vibration that is transmitted in a medium (ex, air) that can be heard. Ultrasound: Is sound waves with frequency higher than upper audible limit of human hearing. Normal human hearing range →(lowest 12 Hz and as high as 20 kHz) Ultrasound uses sound waves with fre...

ULTASOUND INTRODUCTION Sound: Is a vibration that is transmitted in a medium (ex, air) that can be heard. Ultrasound: Is sound waves with frequency higher than upper audible limit of human hearing. Normal human hearing range →(lowest 12 Hz and as high as 20 kHz) Ultrasound uses sound waves with frequencies typically between 2 and 20 MHz :Tissue Interaction. Reflection: Sound waves are reflected when they hit a boundary between two tissues of different densities. Absorption: Some sound waves are absorbed by tissues, reducing the amount of echo returned. Refraction: Waves may change direction when passing through tissues of different speeds. Basic Terminology Echogenicity: The ability of tissues to reflect sound waves: Hyperechoic: Bright (e.g., bone, fat). Isoechoic: Similar to surrounding tissues. Hypoechoic: Darker (e.g., muscle). Anechoic: Black (e.g., fluid-filled structures like cysts or the bladder). Ultrasound waves can penetrate through: 1. Fluid we will see a black picture in the monitor, if US waves penetrated through fluids. 2. Soft tissue (partial reflection) Each organ tissue has characteristic reflection. Which depends on two factors: 1. Density of medium 2. Velocity of sound waves →The amount reflected depends on the difference in acoustic impedance between the two tissues traversed by the beam. What is impedance? Is the ability of tissues or organs to reflect back U/S waves  COMPONANT 1. Transducer (prob) It’s the main part, represents the mouth and ears of the device. Sending signals --- receiving signals It contains: Soft plastic layer covering piezoelectric crystal materials. →It provides brief pulses of US when stimulated by a train of voltage spikes of 1-2 m/sec (duration) 2. Cable: Conducts the signals Contains two wires, electrical wire, and signal wire. Types of Ultrasound Probes Linear Probe: High frequency (5-15 MHz), used for superficial structures (e.g., thyroid, blood vessels). Curvilinear Probe: Lower frequency (2-5 MHz), used for abdominal and pelvic imaging. Phased Array Probe: Narrow beam, useful for imaging cardiac structures and between ribs. Endocavitary Probe: Used for transvaginal or transrectal ultrasound. Basic Ultrasound Modes 1. B-mode (Brightness Mode): Produces a 2D grayscale image of the structures, showing different echogenicity (brightness) based on tissue density. 2. M-mode (Motion Mode): Records the motion of structures (e.g., heart valves) over time. 3. Doppler Mode: Used to assess blood flow and velocity: Color Doppler: Shows blood flow direction and velocity. Spectral Doppler: Provides a waveform representing blood flow velocity over time. Power Doppler: More sensitive to low-flow states but does not show direction  Doppler US When an object reflecting US waves is moving, it changes the frequency of the echoes, creating a higher frequency if its moving towards the probe, and a lower frequency of its moving away from the prob. How much the frequency is changed, depends on how fast the objects is moving. Doppler US measures the changes in frequency of echoes to calculate how fast an object is moving. Doppler US has been used mostly to measure the rate of blood flow through the heart, arteries and veins. Doppler Orientation The long axis of the probe “slices” through the body. There are two main planes in ultrasound – the transverse section (TS), and the longitudinal section (LS). In transverse section, the left side of the image is the right side of the patient. In longitudinal section (also known as sagittal section), the left side of the image is in the direction of the patient’s head :Artifacts Misrepresentations in ultrasound images, such as: Acoustic shadowing: Dark area behind a dense object (e.g., gallstones). Posterior enhancement: Bright area behind a fluid-filled structure. Reverberation: Repeated echoes creating a comet tail effect. ABD ULTRASOND Assesses liver, kidneys, gallbladder, pancreas, and spleen. Liver : homogenies Kidney :homogenies ,medulla hyperechoic fat, hypoechoic calculus Gallbladder :anechoic ,free echo Pancreas :homogenies ,hyper than liver Spleen :homogenies Kidney haydronphrosis MSK ULTRASOUD : Assesses tendons, muscles, and joints for injuries Shoulder US Knee US MSK Knee US Pelvic and obstetrical US us: Evaluates the uterus, ovaries, and bladder. : Monitors fetal growth and development during pregnancy. Uterus US Cardiac Ultrasound :(Echocardiography). Assesses heart function and structure. SMALL PART AND SOFT TISSUE US Asses of thyroid,breast,scrotal and others soft tissue Thyroid US Advantages and Limitations Advantages: Safe (no ionizing radiation). Real-time imaging. Portable and relatively inexpensive. Limitations: Limited penetration in obese or gassy patients. Operator-dependent (requires skill and experience). Limited imaging of structures behind bone or air-filled areas.  BREAK BREAK ULTRASOUND THERAPY Ultrasound therapy is a common treatment modality used in physiotherapy to promote tissue healing, reduce pain, and improve mobility What is Therapeutic Ultrasound? Therapeutic ultrasound is a physical therapy treatment that uses sound waves (high-frequency vibrations) to penetrate tissues. It works by creating deep heating or mechanical effects in tissues, helping to accelerate the body's natural healing process. Types of Ultrasound. Continuous Ultrasound: Delivers constant sound waves, providing a thermal effect (deep heating). It is used for chronic conditions, muscle relaxation, and increasing blood flow. Pulsed Ultrasound: Delivers sound waves in pulses, producing non-thermal effects. It is used for acute injuries and to reduce inflammation. How Ultrasound Works Ultrasound waves are produced by a piezoelectric crystal in the ultrasound head (transducer). When the transducer is placed on the skin, it emits sound waves that travel through tissues. These waves can cause mechanical vibration and heating of tissues, depending on the settings used. Physiological Effects of Ultrasound. Thermal Effects: Increases tissue temperature Enhances blood circulation Reduces muscle spasm Increases tissue extensibility (useful for stretching) Non-Thermal Effects: Enhances cell membrane permeability Promotes tissue repair and healing Reduces inflammation and swelling Ultrasound Parameters. Understanding and adjusting the settings is crucial for effective treatment: Frequency: 1 MHz: Deep penetration (up to 5 cm), suitable for deep tissues like muscles. 3 MHz: Superficial penetration (1-2 cm), suitable for tendons and ligaments. Intensity: Measured in watts per square centimeter (W/cm²). 0.5-1.0 W/cm²: Low intensity, typically for acute conditions or sensitive areas. 1.0-2.0 W/cm²: Moderate intensity, for subacute or chronic conditions. Above 2.0 W/cm²: Higher intensity, less commonly used. Duty Cycle: The percentage of time the ultrasound is emitting waves. 100% (Continuous): Produces thermal effects. 20%-50% (Pulsed): Reduces heat and is used for non-thermal effects. Time: Generally, 5-10 minutes per area, depending on the size and condition being treated. Application Techniques Coupling Medium: Ultrasound waves cannot travel through air, so a coupling gel is used between the transducer and the skin. The gel helps transmit the waves effectively into the tissue. Direct Contact: The transducer is placed directly on the skin with a layer of gel. Move the transducer in slow circular or linear motions to avoid tissue damage and ensure even distribution. time: Typically, 5-10 minutes per treatment area. Indications Ultrasound can be used for: Muscle strains and sprains Tendonitis and bursitis Joint stiffness and scar tissue Pain management (e.g., arthritis) Contraindications Do not use ultrasound therapy on: Open wounds or infected areas Over metal implants without proper assessment Pregnant abdomen or lower back During pregnancy (avoid treating the abdomen or lower back) Malignant tumors or cancerous areas Eyes, heart, or reproductive organs Safety Tips Always test the ultrasound machine before using it on a patient. Always use a coupling gel. Keep the transducer moving continuously. to prevent burns or tissue damage Monitor patient feedback for discomfort or pain. Start with lower intensities and adjust as needed. END ALL THE BEST