FIELD OF TECHNOLOGY:
Ultrasound
INVENTION
TITLE:�
Method and
Apparatus for High-Resolution and High-Frame-Rate Ultrasonic Spatial
Compounding Imaging at a Region of Interest
PROBLEM/BACKGROUND:�
The current
available spatial compounding imaging technology causes undesirable smearing on
moving tissue due to its low effective frame rate. This disadvantage makes
spatial compounding less useful for vascular and/or cardiac applications. In
general, the spatial resolution is also degraded due to the reduction in the
number of vectors fired per frame in order to reach a decent frame rate.
In many
clinical applications, only certain critical (suspicious) regions of the entire
image need to be evaluated with improved contrast resolution (or reduced
speckle.) This invention provides a solution for these clinical situations, in
that spatial compounding is performed only in the region of interest (ROI).
Beyond ROI, the image areas consist of pixels formed only from non-steered
frame. By using this technique, the total number of vectors fired per compound
image is reduced dramatically compared to the conventional spatial compounding
technique, as most often the ROI size is only a small fraction of the entire
image size. Therefore, without too much reduction on frame rate, spatial
resolution inside the ROI can be improved by using high vector line density
within the ROI. Also, the overall spatial resolution can be improved by using
high vector line density for the non-steered frame.
INVENTION
DESCRIPTION:�
The
procedure of this invention is summarized as following:
1.
User selects region of interest (ROI).�
This can be done by placing a ROI box on the image as used in colorflow
imaging.
2. Based on the size and location of the ROI box, the scanner
computes vector sets to be fired from each steered
angle in order to fully cover the ROI box.
3. For each scan cycle, the scanner first fires full vector
set at the non-steered direction and then fires the computed vector sets for
each steering angle sequentially. Here, the number of vectors fired at each
steered direction is only a fraction of the total number of vectors available
per frame. The scan cycle is repeated until the scan is stopped or imaging
setting is changed by the user.
4. The scanner displays the entire image and updates the
image whenever the firing at one of the directions is completed. Only the ROI
box covered by the selected vector set from this steered direction is updated.
The updating is implemented by subtracting the old data from the compound
region and adding the new data to it. Other region of the image remains
unchanged. Proper weighting may be applied to enforce uniform gain of the
entire image and smooth transition between the ROI box (compound region) and
the area surrounding it.
An
alternative approach is to display the ROI only. The procedure is the
following:
1.
User selects region of interest (ROI).�
This can be done by placing a ROI box on the image as used in colorflow
imagi...