• Ferrara, Katherine W (PI)

Project: Research project

Project Details


In this new research, wideband velocity estimation techniques developed by
the principal investigator, using the return from an acoustic signal, will
be applied to the problem of the estimation of the blood velocity profile.
Due to the use of narrowband estimators with limited spatial and velocity
resolution, ultrasonic instruments with a single sample volume cannot
currently provide a reliable estimate of velocity spread in small spatial
regions, thus limiting the detection of stenotic arterial lesions which
encompass less than 50% of the vessel diameter. In addition, current
instruments are limited in their detection of slow flow through small
vessels, due to the requirement for the transmission of a narrowband
signal, and the insensitivity of current clutter rejection, or wall
filters. It is anticipated that the new wideband estimation approach will
establish a more rigorous limiting performance in blood flow estimation,
and provide an improved methodology for the study of the physiology of the
circulatory system, as well as the detection and quantification of heart
and vascular abnormalities. Using a wideband transmitted signal, optimal estimation of mean velocity
and velocity spread within each small spatial region will be studied for
these long observation intervals, first through a theoretical development.
This will include a theoretical evaluation of the fundamental limitations
on the detection of disturbed flow, and the fundamental limitations on the
detection of low velocity flow through small vessels. This research will
include the use of alternative signaling schemes, as well as proposed three
dimensional spatial velocity plots. Experimental data will then be
acquired and analyzed in order to complement the theoretical results. This
data will be acquired from phantom vessels with varying degrees of
stenosis, variations in vessel size, and variations in vessel orientation. In addition to a potential improvement in the understanding of the behavior
of small volumes of the blood scattering medium, the defined research
project could produce several important improvements in flow estimation.
First, an improved sensitivity to low velocity flow through small vessels
could significantly improve the detection of small vascularized tumors.
Second, the principal investigator has previously shown that the new
wideband strategies are very sensitive to the width of the illuminated
velocity distribution, and can therefore significantly improve the
estimation of turbulence, which is extremely important in assessment of
pathology. In addition, new wideband techniques can eliminate aliasing,
which affects narrowband techniques and therefore current instruments.
Effective start/end date9/30/929/29/95


  • National Institutes of Health


  • Medicine(all)


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