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Spectral resolution, that define the smallest spectral variation that the system is able of distinguish; Radiometric accuracy, that says how accurate is the system in measuring the spectral reflectance percentage; The most used way to achieve spectral imaging is to take an image for each desired band, using a narrowband filters.
Meanwhile, spectral Doppler ultrasonography consists of three components: B-mode, Doppler mode, and spectral waveform displayed at the lower half of the image. Therefore, "duplex ultrasonography" is a misnomer for spectral Doppler ultrasonography, and more exact name should be "triplex ultrasonography".
Medical ultrasound includes diagnostic techniques (mainly imaging techniques) using ultrasound, as well as therapeutic applications of ultrasound. In diagnosis, it is used to create an image of internal body structures such as tendons, muscles, joints, blood vessels, and internal organs, to measure some characteristics (e.g., distances and velocities) or to generate an informative audible sound.
Spectral doppler through pulmonary vein. Spectral doppler is presented similarly to M-mode in which the doppler information is plotted as a spectrogram. This can be both "continuous" and "pulse" wave where the former shows the spectrum along a specific line and the latter shows within a small window along that line.
In the fields of cardiology and medical imaging, speckle tracking echocardiography (STE) is an echocardiographic imaging technique. It analyzes the motion of tissues in the heart by using the naturally occurring speckle pattern in the myocardium (or motion of blood when imaged by ultrasound).
Two methods of recording may be used for this procedure. The first uses "B-mode" imaging, which displays a 2-dimensional image of the skull, brain, and blood vessels as seen by the ultrasound probe. Once the desired blood vessel is found, blood flow velocities may be measured with a pulsed Doppler effect probe, which graphs velocities over time.
Unlike 1D Doppler imaging, which can only provide one-dimensional velocity and has dependency on the beam to flow angle, [4] 2D velocity estimation using Doppler ultrasound is able to generate velocity vectors with axial and lateral velocity components. 2D velocity is useful even if complex flow conditions such as stenosis and bifurcation exist ...
Sensitivity also depends on the ultrasound detector employed, the amount of light energy applied, the voxel size and spectral unmixing method. As imaging depth increases, light and ultrasound attenuation together reduce the optoacoustic signal and therefore the overall detection sensitivity.