What is spectral broadening?
What is spectral broadening?
Spectral broadening is caused by turbulence in blood flow as the normally homogeneous velocity of reflective red blood cells becomes more diverse, resulting in the apparent broadening of the spectral Doppler waveform.
What is intrinsic spectral broadening?
Intrinsic spectral broadening ISB is broadening of the Doppler spectrum that is an artifact, related to the scanner rather than the blood flow interrogated.
What is B mode sonography?
B-Mode is a two-dimensional ultrasound image display composed of bright dots representing the ultrasound echoes. The brightness of each dot is determined by the amplitude of the returned echo signal.
What does spectral broadening look like?
The spectral window is the clear black zone between the spectral line and the baseline. Widening of the spectral line and filling of the spectral window is called spectral broadening. Spectral broadening is normally seen in the presence of high flow velocity, at the branching of a vessel, or in small-diameter vessels.
What is aliasing in echocardiography?
Aliasing is an imaging error when information of velocity of the blood flow is higher than the Nyquist velocity. The Nyquist velocity may set on color Doppler echocardiography tools. The blood flows velocity displays as scale and direction in the range of Nyquist velocity.
What is Doppler line broadening measured in?
Saturated absorption spectroscopy, also known as Doppler-free spectroscopy, can be used to find the true frequency of an atomic transition without cooling a sample down to temperatures at which the Doppler broadening is minimal.
What is an M-mode?
M-mode or “motion” mode is a form of ultrasound imaging that is of high clinical utility in the emergency department. It can be used in a variety of situations to evaluate motion and timing, and can document tissue movement in a still image when the recording of a video clip is not feasible.
What are AB and M scans?
Four different modes of ultrasound are used in medical imaging (1, 3). These are: B-mode: In B-mode ultrasound, a linear array of transducers simultaneously scans a plane through the body that can be viewed as a two-dimensional image on screen. M-mode: M stands for motion.
When does artifactual spectral broadening occur in ultrasound?
Artifactual spectral broadening is dependent on the angle of insonation and will increase as the angle approaches 90°. Maintaining a proper orientation (<60°) of the ultrasound beam can minimize this artifact 2. Care must be taken to use an appropriately sized sample volume within the interrogated blood vessel.
Why is spectral broadening important in pulsed wave ultrasound?
Spectral broadening is an important artifact in pulsed wave Doppler ultrasound imaging, due to its clinical relevance as a sign of vessel stenosis.
When to use spectral broadening in Arterial doppler imaging?
Spectral broadening is a valuable sign in arterial Doppler imaging, e.g. in the assessment of the carotids. It can signal the development of significant stenosis in difficult situations where e.g. direct measurement in the most stenotic areas is not possible due to circumferential atherosclerotic plaques resulting in complete acoustic shadowing.
What does it mean when spectral waveform broadens?
Observing spectral waveform broadening distal to this “black box” segment indirectly indicates significant narrowing. However, care must be taken to use a proper measurement technique in order to avoid spurious broadening of the spectrum.
