Ultrasound History, Physics, and Clinical Applications

Vocabulary flashcards covering key terms related to the physics, history, imaging modes, clinical specialties, and emerging technologies in diagnostic and therapeutic ultrasound.

Sound

Mechanical energy created by a vibrating source that moves molecules back and forth, forming waves.

Acoustics

The scientific study of sound—its production, transmission, and effects.

Pebble Theory

Boethius’ analogy that sound waves spread like ripples after a pebble is dropped into water.

Medium (for sound)

Any physical substance (air, tissue, water, etc.) required for sound propagation; without it, sound cannot travel.

Coupling Gel

Water-based gel applied between transducer and skin to eliminate air and transmit ultrasound efficiently.

Echolocation

Biological use of reflected sound waves (e.g., bats) to locate objects; foundation for pulse-echo ultrasound.

Pulse-Echo Technique

Method where short ultrasound pulses are emitted and returning echoes are analyzed to form images.

Doppler Effect

Change in frequency of a sound wave when the source and listener move relative to one another; used to assess blood flow.

Piezoelectric Effect

Property of certain crystals to generate electricity when compressed and vibrate when voltage is applied, producing ultrasound.

Sonar

WWI technology that sends sound through water to detect submarines by analyzing returned echoes.

Reflectoscope

Firestone’s device that adapted sonar to find flaws in metal, a precursor to medical ultrasound.

A-Mode (Amplitude Mode)

One-dimensional display plotting echo depth (x-axis) versus echo strength (y-axis).

B-Mode (Brightness Mode)

Two-dimensional grayscale display where dot brightness reflects echo strength, forming anatomical images.

M-Mode (Motion Mode)

Graph of depth versus time along a single scan line to document movement, e.g., fetal or cardiac motion.

Continuous Wave Doppler

Technique that transmits and receives ultrasound continuously to record high-velocity blood flow.

Pulsed Wave Doppler

Doppler method sending short bursts, enabling velocity measurements at a specific depth.

Duplex Imaging

Simultaneous B-mode anatomy with spectral Doppler flow data in one display.

Triplex Imaging

Combination of B-mode, spectral Doppler, and color Doppler for comprehensive anatomic and flow assessment.

Tissue Harmonic Imaging

Uses harmonic frequencies generated within tissue to create crisper images with improved resolution.

3D Ultrasound

Reconstructs width, height, and depth for volumetric images, useful in obstetrics and other fields.

4D Ultrasound

Real-time 3D imaging that adds the dimension of time, showing motion in three dimensions.

Volumetric Imaging

Acquisition of a full data set by a single sweep, then computer reconstruction, reducing operator dependence.

Abdominal Sonography

Ultrasound evaluation of abdominal organs using 2–5 MHz transducers and Doppler for vascular assessment.

Small Parts Sonography

Imaging of superficial structures such as thyroid, scrotum, prostate, breast, and tendons with high-frequency probes.

Breast Sonography

High-frequency ultrasound that differentiates cystic from solid breast masses and guides interventions.

Neurosonography

Ultrasound imaging of neonatal brain, infant spine, or intraoperative cerebral structures via acoustic windows.

Pediatric Sonography

Adaptation of adult protocols for infants and children, encompassing neuro, abdominal, and other studies.

Musculoskeletal Sonography

Evaluation of joints, tendons, muscles, and foreign bodies in the extremities with high-resolution probes.

Gynecologic Sonography

Ultrasound assessment of female pelvic organs, typically with a full bladder for transabdominal views.

Transvaginal Sonography

Intracavitary pelvic scanning with ≥5 MHz probes, offering high-resolution images without bladder filling.

Saline Infusion Sonohysterography

Injection of sterile saline into the uterus to delineate the endometrium and cavity under ultrasound guidance.

Obstetric Sonography

Ultrasound imaging of pregnancy across trimesters to assess fetal and maternal well-being.

Fetal Echocardiography

Specialized ultrasound examination focused on detailed fetal heart anatomy and function.

Vascular Sonography

Doppler-based evaluation of arterial and venous systems in limbs, neck, and abdomen.

Echocardiography

Ultrasound study of heart anatomy and hemodynamics using 2D imaging, M-mode, and Doppler.

Transthoracic Echocardiogram (TTE)

Standard non-invasive cardiac ultrasound obtained through the chest wall.

Transesophageal Echocardiogram (TEE)

Invasive cardiac ultrasound performed from the esophagus for closer heart visualization.

Stress Echocardiogram

Cardiac ultrasound during or after exercise or pharmacologic stress to assess function under load.

Therapeutic Ultrasound

Use of ultrasound energy to heat tissue, enhancing blood flow and speeding healing.

High-Intensity Focused Ultrasound (HIFU)

Focused ultrasound that thermally ablates targeted tissue such as tumors or fibroids.

Contrast-Enhanced Ultrasound

Administration of microbubble contrast agents to improve visualization of vessels and lesion borders.

Ultrasound Elastography

Technique evaluating tissue stiffness to help distinguish benign from malignant masses.

Fusion Imaging

Overlay of prior CT/MRI images with real-time ultrasound to guide procedures and correlate findings.

Intravascular Ultrasound (IVUS)

Miniature probe placed inside vessels to image the vessel wall from within.

Focused Assessment with Sonography for Trauma (FAST)

Rapid bedside ultrasound exam to detect free fluid or bleeding in trauma patients.

Automated Ultrasound Systems

Computer-driven scanners performing standardized sweeps for improved reproducibility and less operator dependence.

Wireless Transducer Technology

Cordless probes that transmit data to the ultrasound machine, enhancing maneuverability and reducing clutter.

Piezoelectric Crystals

Active elements in transducers that convert electrical energy to ultrasound and receive returning echoes.