Ultrasound and Stethoscope Fundamentals

A modern stethoscope consists of a bell with a diaphragm, tubing, and earpieces.

The frequency of sounds must resonate in the bell membrane, which is influenced by the bell's diameter and diaphragm tension.

Ultrasound is sound with a frequency range of 20kHz to 1GHz, which is above the upper limit of human hearing.

<p>A transducer converts electrical energy to mechanical energy to generate ultrasound waves and vice versa.</p> Signup and view all the answers

<p>SONAR uses ultrasound waves to generate images of soft tissue structures in the body.</p> Signup and view all the answers

<p>Gel or water is used to eliminate air and create good impedance matching between the transducer and skin.</p> Signup and view all the answers

<p>The pulse reflects off tissues and the echoes are detected, amplified, and displayed on an oscilloscope.</p> Signup and view all the answers

<p>The bell's diameter affects the selection of frequency ranges that can be effectively picked up.</p> Signup and view all the answers

<p>The focal zone enhances the spatial resolution and clarity of the ultrasound image by concentrating the sound waves in a specific area.</p> Signup and view all the answers

<p>Acoustic impedance is the measure of resistance encountered by an ultrasound wave at a tissue boundary, affecting how much wave energy is reflected or transmitted.</p> Signup and view all the answers

<p>Refraction can change the direction of ultrasound waves as they pass between tissues of different velocities, potentially causing image distortions.</p> Signup and view all the answers

<p>Quality is determined by factors such as spatial resolution, attenuation, reflection, and transmission of the ultrasound waves through tissue.</p> Signup and view all the answers

<p>Attenuation leads to an exponential decrease in the intensity of the ultrasound beam as it propagates through tissues, due to absorption and scattering.</p> Signup and view all the answers

<p>Perpendicular reflections provide clear echo signals, while non-perpendicular reflections result in intensity loss, affecting image quality.</p> Signup and view all the answers

<p>Higher resolution requires stronger frequencies, which reduces penetration depth, creating a compromise between these two qualities.</p> Signup and view all the answers

<p>Air bubbles can disrupt ultrasound wave transmission, leading to poor image quality; using a thick liquid medium helps eliminate air pockets.</p> Signup and view all the answers

<p>The speed of sound is determined by the medium's elasticity and density, traveling fastest in solids and slowest in gases.</p> Signup and view all the answers

<p>Frequency and wavelength are inversely related; as frequency increases, wavelength decreases, expressed mathematically as $v = f \lambda$.</p> Signup and view all the answers

<p>Infrasound refers to sound frequencies below 20 Hz, which are inaudible to humans, while audible sound ranges between 20 Hz to 20 kHz.</p> Signup and view all the answers

<p>Sonar operates on the principle of sending sound waves and analyzing their reflections to generate images of underwater objects or structures.</p> Signup and view all the answers

<p>A stethoscope amplifies internal body sounds, allowing healthcare providers to assess heartbeats, breathing, and other bodily functions.</p> Signup and view all the answers

<p>Wavelength is the distance between successive compressions and rarefactions in a sound wave.</p> Signup and view all the answers

<p>The intensity level measures the power of sound per unit area, affecting how loud or soft a sound appears to human ears.</p> Signup and view all the answers

<p>The quality of US images is influenced by factors such as frequency, transducer design, and the medium's properties.</p> Signup and view all the answers

<p>Common symptoms include respiratory impairment, aural pain, fear, visual hallucinations, and chills.</p> Signup and view all the answers

<p>Infrasonic sound travels long distances with low absorption and large wavelength, affecting most media.</p> Signup and view all the answers

<p>It measures micro-vibrations in the infrasonic range associated with heart contraction and blood ejection.</p> Signup and view all the answers

<p>Loudness refers to the intensity of the sound perceived, while pitch determines whether it is high or low.</p> Signup and view all the answers

<p>A portion of the wave is reflected while another is transmitted, with the reflection ratio depending on the impedance difference.</p> Signup and view all the answers

<p>Sound intensity is the energy carried by the wave per unit area and per unit time, typically measured in W/.</p> Signup and view all the answers

<p>Ultrasound refers to sound waves above 20KHz and is used in various medical specialties for imaging due to its safety and detailed information.</p> Signup and view all the answers

<p>A large difference results in high reflection and low transmission of sound waves.</p> Signup and view all the answers

<p>A smooth surface results in low scattering which leads to a good image, while a rough surface causes high scattering resulting in a poor image.</p> Signup and view all the answers

<p>A-mode ultrasound measures depth by calculating the time taken for reflected sound waves to return, using the formula Depth = Velocity x time.</p> Signup and view all the answers

<p>An abnormal shift is greater than 3 mm for adults and greater than 2 mm for children.</p> Signup and view all the answers

<p>A-mode ultrasound is used for diagnosing eye diseases and for biometry measurements related to the eye.</p> Signup and view all the answers

<p>B-mode ultrasound provides 2D images of internal body structures, and it differs from A-mode by using a moving transducer.</p> Signup and view all the answers

<p>M-mode ultrasound studies motion, particularly cardiac motion, and combines features by using a stationary transducer like A-mode while displaying data as dots like B-mode.</p> Signup and view all the answers

<p>High-frequency ultrasound produces better resolution images because there is minimal absorption of sound energy in the small eye structures.</p> Signup and view all the answers

<p>B-mode ultrasound forms images by utilizing a storage oscilloscope to visualize echoes from a moving transducer.</p> Signup and view all the answers

A mechanical disturbance that travels through a medium as a wave, caused by vibrations, and characterized by compressions and rarefactions.

The speed at which a sound wave travels through a medium.

The number of compressions or rarefactions that pass a point in a given time, measured in Hertz (Hz).

The distance between two successive compressions or rarefactions in a sound wave, measured in meters (m).

A measure of the sound wave's amplitude, indicating the intensity of the sound.

Sound frequencies below the range that humans can hear (typically below 20 Hz).

Sound frequencies within the range that humans can hear (typically 20 Hz to 20 kHz).

Sound frequencies above the range that humans can hear (typically above 20 kHz).

Infrasound is sound waves with frequencies below the human hearing range (20Hz).

Infrasound can travel long distances without losing much energy due to its low absorption and large wavelength.

Infrasound can pass through various materials such as air, water, and even solid objects.

Infrasound can cause various effects on the human body, including respiratory problems, pain in the ears, fear, visual hallucinations, and chills.

Ultrasound is sound waves with frequencies above the human hearing range (20kHz).

Ultrasound is used in medical imaging to visualize internal organs and tissues due to its ability to penetrate the body and reflect back.

The intensity of a sound wave is the amount of energy it carries per unit area per unit time.

Sound intensity level is a measure of how loud a sound is compared to a reference level.

A medical instrument used to amplify sounds made by the body from the heart, lungs, or other body sites. It consists of a bell, tubing, and earpieces.

The process by which a transducer converts electrical energy into mechanical (ultrasound) energy and vice versa. It is based on the piezoelectric principle.

A device that uses ultrasound waves to generate an image of a particular soft tissue structure in the body.

A sensor that converts electrical energy into mechanical (ultrasound) energy and vice versa, used in ultrasound imaging.

A type of transducer that converts electrical energy into mechanical energy (sound waves) when an electric potential difference is applied across its faces.

The natural frequency of a stethoscope's bell, which depends on the diameter and tension of the diaphragm.

The matching of impedance between the stethoscope's bell and the air in the tube, ensuring efficient sound transmission.

The area where ultrasound waves are focused, resulting in the clearest image. It's like using a magnifying glass to focus sunlight on a specific spot.

A measure of how easily sound waves travel through a medium. It's like resistance to sound.

The bending of sound waves as they pass from one tissue to another. It's like a straw in a glass of water making the straw appear bent.

The sharpness of the image, determined by how well the ultrasound scanner can distinguish between tiny details in tissue

The weakening of ultrasound waves as they travel through tissue. It's like sound fading as it travels a distance.

The redirection of sound waves from a surface back to the transducer. It's like throwing a ball at a wall and it bouncing back.

The ability of sound waves to pass through tissue. It's like sound passing through a window.

A trade-off between image quality and how deeply the ultrasound can penetrate into the body. It's like choosing a lens with greater magnification but less overall image coverage.

A mode is a 1D ultrasound imaging technique that measures the depth of structures by sending sound waves into the body and recording the time it takes for the echoes to return.

A-mode ultrasound is used to diagnose brain tumors by sending pulses of ultrasound to the skull above the ear and measuring the echo shifts from different structures.

A-mode ultrasound is used in ophthalmology to measure distances within the eye, such as lens thickness, depth to the retina, and vitreous tumor thickness, using high-frequency sound waves.

B-mode ultrasound creates 2D images by moving the transducer across the body, similar to A-mode but with a scanning motion.

B-mode ultrasound is used to visualize internal structures of the body, such as the size, position, and changes over time of the eye, liver, breast, heart, and fetus.

M- mode ultrasound combines A-mode's stationary transducer with B-mode's dot-based display to study motion, particularly of the heart and its valves.

M-mode is used to observe the movements of the heart and heart valves, providing information about their function and potential abnormalities.

Rough surfaces scatter sound waves more, resulting in blurry or noisy images, while smooth surfaces scatter less, producing clearer images.