A method and apparatus for adjusting the shape of a region of interest (R01) in a frame of imaging data in response to an operator-actuated change in the depth of the ROI is described. The displayed image has a back-ground region of data acquired using a first imaging mode and an ROI of data acquired using a second imaging mode. The ROI is surrounded by the background region and bounded by an ROI graphic. The adjustment in the shape of the ROI is accomplished by programming the imaging system with an algorithm that maintains the height and the bottom width of the ROI substantially constant. Only the top width of the ROI and the angles of the edge lines are automatically changed in response to the operator-actuated change in ROI depth.
