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In physics, particularly within medical and ultrasound imaging, bandwidth refers to the range of frequencies present in an ultrasound pulse. A broader bandwidth allows for shorter pulses, which directly translates to improved axial resolution. This enhanced resolution is crucial for distinguishing between closely spaced structures within the body, providing more detailed and accurate diagnostic images.…

In medical ultrasound physics, pulse duration refers to the actual time a single ultrasound pulse is active, from the beginning to the end of its transmission. Measured in microseconds, it's determined by the number of cycles within the pulse multiplied by the period of each cycle. A shorter pulse duration enhances axial resolution, allowing for…

In physics, Continuous-wave (CW) Doppler is an ultrasound technique that continuously transmits and receives sound waves. This allows for the measurement of very high blood flow velocities, crucial in medical diagnostics where precise speed is paramount. Unlike pulsed-wave Doppler, CW Doppler doesn't suffer from aliasing, making it ideal for assessing rapid, turbulent flows in conditions…

In physics, wavelength is the spatial period of a periodic wave—the distance over which the wave's shape repeats. It's a fundamental property of sound waves, light, and other periodic waves, inversely proportional to frequency. In medical ultrasound, understanding wavelength is critical, as it directly influences image resolution and penetration depth. Shorter wavelengths (higher frequencies) provide…

Pulsed-wave Doppler, in physics, is an ultrasound technique that precisely measures blood flow velocity at a specific location. It emits short bursts of ultrasound waves and then listens for echoes from moving red blood cells. By analyzing the time delay between pulses and the frequency shift (Doppler effect) of the returning echoes, the system can…

In physics, propagation speed in medical ultrasound refers to the rate at which sound waves travel through a medium. This crucial parameter is determined by the density and stiffness of the tissue; sound propagates faster through denser, stiffer tissues like bone than through fluid or fat. Understanding propagation speed is fundamental to accurate depth perception…

In physics, aliasing is a distortion or artifact that occurs when a continuous signal is sampled at a rate too low to accurately capture its true characteristics. This fundamental concept is particularly relevant in medical imaging and ultrasound, where it manifests when the sampling rate (pulse repetition frequency) is insufficient to accurately measure high-velocity blood…

In physics, acoustic impedance mismatch describes the difference in acoustic impedance between two media at their boundary. When sound waves encounter this mismatch, a portion of the wave is reflected, and the remaining portion is transmitted. This principle is fundamental to understanding how ultrasound works in medical imaging. In ultrasound, significant acoustic impedance mismatches, such…

In physics, the Nyquist limit is a fundamental concept in digital signal processing, particularly crucial in medical ultrasound. It states that to accurately reconstruct a signal, the sampling rate must be at least twice the highest frequency component of the original signal. Exceeding this limit leads to aliasing, where high-frequency information is misrepresented as lower…