Page 106 of 148 300004969171/B
to assess quantitative blood flow or to develop a numeric measure of total cross-
sectional blood flow.
The ChromaFlo option can detect blood velocities in the following range:
o The lower limit on particle detection is between 4 cm/sec and 7 cm/sec,
depending on the intervening attenuation. (The higher limit is obtained with
maximum tissue attenuation between the transducer and region of flow.)
o The upper limit on particle detection is between 107 cm/sec and 110 cm/sec,
depending on the intervening attenuation. (The lower limit is obtained with
maximum tissue attenuation between the transducer and region of flow.)
ChromaFlo
detected
Velocity sensitivity of the ChromaFlo technique is
between 4 cm/sec and 7 cm/ sec, depending on the
attenuating tissue between the transducer and the
region of flow. The higher velocity number (lower
sensitivity) is obtained when detecting flow at
depths greater than 8mm. In either situation, flow
below this velocity will appear as black.
and compare the
lumenal boundary
based on grayscale
images with those
obtained from
ChromaFlo images,
as well as other
modalities such as
angiography.
frame rate
Due to processing speeds in ChromaFlo mode, the
overall frame rate of the Volcano system is lowered
to approximately 12 frames per second, which
represents combined grayscale and color features.
moving structures
may appear to move
in a more continuous
manner during
standard, non-
ChromaFlo imaging.
coded as color
The ChromaFlo technique uses the changing IQ
“speckle” pattern to detect regions of flow. It is
possible for tissue motions to generate speckle that
is detected as a flow region. The ChromaFlo
processor employs a sensitivity control which
discriminates between tissue and flow regions
based on the magnitude of the grayscale image.
For example, a bright reflector, even though it
generates an echo which is decoded as flow, is
suppressed. A lower level signal is not suppressed.
This is based on the clinical findings in which blood
interest as necessary
to prevent tissue
from being coded as
color.
To Next Page
Loading...
General