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Axial resolution in physics, particularly relevant to medical ultrasound, defines the ability to distinguish two structures positioned along the ultrasound beam's axis as separate entities. This crucial parameter is directly influenced by the spatial pulse length; shorter pulses, achieved with higher frequencies and fewer cycles, lead to superior axial resolution. Optimized axial resolution is essential…

In physics, particularly within medical ultrasound, lateral resolution refers to the ability of an imaging system to distinguish two closely spaced objects that are perpendicular to the ultrasound beam. This crucial parameter is influenced by beam width and focus, directly impacting the clarity and detail of structures displayed on the image. Achieving high lateral resolution…

In physics, scattering describes the redirection of waves, like sound or light, as they encounter obstacles or inhomogeneities within a medium. This fundamental phenomenon is crucial in medical imaging, particularly in ultrasound, where sound waves interact with various tissues. Understanding scattering helps explain the speckled appearance of ultrasound images and how different tissues reflect sound.…

In physics, impedance is the opposition a system presents to the flow of energy. In the context of medical ultrasound, acoustic impedance is a critical property of tissue, defined as the product of tissue density and the speed of sound within that tissue. This fundamental concept dictates how sound waves behave at interfaces between different…

In physics, the Doppler effect describes the change in frequency or wavelength of a wave in relation to an observer who is moving relative to the wave source. When the source and observer are moving closer, the frequency appears higher (shorter wavelength), and when they are moving apart, the frequency appears lower (longer wavelength). This…

In ultrasound physics, Pulse Repetition Frequency (PRF) is a critical parameter referring to the number of ultrasound pulses emitted by the transducer per second. Measured in Hertz (Hz) or kilohertz (kHz), PRF directly influences the maximum depth from which echoes can be accurately received before the next pulse is sent. A higher PRF allows for…

Color Doppler, a vital ultrasound physics principle, visually represents blood flow direction and velocity. This technique leverages the Doppler effect, where sound waves reflecting off moving red blood cells change frequency. The ultrasound system processes these frequency shifts, assigning different colors (typically red for flow towards the transducer and blue for flow away) to indicate…

In physics, Spectral Doppler is an advanced ultrasound technique that analyzes the full range of blood flow velocities within a vessel, displaying them as a waveform over time. This method provides critical quantitative data on blood flow direction, speed, and characteristics, enabling precise diagnostic assessments. It's fundamental for evaluating arterial and venous pathologies, such as…

In ultrasound physics, Power Doppler is a highly sensitive imaging mode that detects the presence and magnitude of blood flow by measuring the amplitude of the Doppler signal, rather than its direction or velocity. This makes it particularly useful for visualizing low-velocity flows, small vessels, or when the vessel is perpendicular to the ultrasound beam,…