High Resolution & High Frame Rate Ultrasonic Spatial Compounding Imaging

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...