Robert W. Steins

Morphing diagnostic ultrasound images for perfusion assessment

An ultrasound image is morphed for perfusion assessment. Various images within a sequence of images or movie clip are mapped to one frame of reference using local warping. Nonlinear local image transformations or other warping based on local estimates of motion are used to interpolate different images to the common reference. The elastic stretching and compression of local image data results in a sequence of images where the same spatial location in each image represents the substantially same spatial location of the imaged tissue. The organ, tissue or region of interest is stationary throughout the sequence of images.

Removing local motion from ultrasonic images using nonaffine registration for contrast quantification

A contrast quantification package has been developed to be part of a medical ultrasound system. This package provides motion compensation through nonaffine image registration. An explanation of the image registration system is given. A set of analyses made with this system is presented; they show that the registration system provides significant improvements over using images without motion correction.

Synthetic transmit beam steering for spatial compounding applications using continuous transmit focusing

Traditional spatial compounding, in general, employs multiple distinct transmit/receive beam angles which insonify a common region, from which multiple images are formed. The individual images are detected, resampled onto a common grid, and combined in order to produce better image quality, whose attributes are better contrast resolution, reduced speckle, reduced shadowing artifacts, and better borders. However, the increase in image quality comes at a cost in increased acoustic acquisition time, with a corresponding drop in frame rate. Combination modes such as B+CD places heavy demands on acquisition time, and in order to maintain adequate frame rates, the number of B-mode spatial compounding views is reduced or eliminated when in CD-mode, reducing B-mode image quality. In order to provide spatial compounding while maintaining the same acoustic acquisition time, multiple steered transmit beams are synthesized from the same set of channel data acquired for the non-steered view, using a continuous transmit focusing technique.