Abstract
In conventional ultrasound velocity estimation systems
only the velocity projected onto the direction of the steered
ultrasound beam is found. It has previously been shown how
true blood flow velocity magnitudes can be found using synthetic
transmit aperture imaging. The method is based on crosscorrelation
between lines beamformed along the flow direction.
This method assumes the direction of flow is known.
Jensen (2004) presented a method for estimating the direction
of flow [1]. The angle determination method is based on a search
for the maximum normalized cross-correlation as a function of
angle. It assumes the largest correlation is seen for the angle
of flow. Previously, this method has only been validated using
data from a circulating flow rig. This paper presents an In-Vivo
investigation of the method.
Real time data covering 2.2 seconds of the carotid artery of a
healthy 30-year old male volunteer is acquired and then processed
off-line using a large computer cluster.
Data are acquired using our RASMUS experimental ultrasound
scanner and a 128 element 6.2 MHz linear array
transducer. A 20 µs chirp was used during emission and virtual
transmit sources were created behind the transducer using 11
transmitting elements. Data from 8 transmissions with each 64
receiving elements are beamformed and coherently summed to
create high resolution lines at different angles for a set of points
within the region of flow. The pulse repetition frequency was set
to 10 kHz.
The direction of flow is estimated using the above mentioned
method. It is compared to the flow angle of 106◦ with respect to
the axial direction, determined visually from the B-mode image.
For a point in the center of the common carotid artery, 76 % of
the flow angle estimates over the 2.2 seconds were within ±10◦
of the visually determined flow angle. The standard deviation of
these estimates was below 2.7◦.
Full color flow maps from different parts of the cardiac cycle
are presented, including vector arrows indicating both estimated
flow direction and velocity magnitude.
| Original language | English |
|---|---|
| Title of host publication | Proceedings of 2005 IEEE Ultrasonics Symposium |
| Publisher | IEEE |
| Publication date | 2005 |
| Pages | 1331-1334 |
| ISBN (Print) | 0-7803-9383-X |
| DOIs | |
| Publication status | Published - 2005 |
| Event | 2005 IEEE Ultrasonics Symposium - Rotterdam, Netherlands Duration: 18 Sept 2005 → 21 Sept 2005 http://ieeexplore.ieee.org/xpl/mostRecentIssue.jsp?punumber=10674 |
Conference
| Conference | 2005 IEEE Ultrasonics Symposium |
|---|---|
| Country/Territory | Netherlands |
| City | Rotterdam |
| Period | 18/09/2005 → 21/09/2005 |
| Internet address |