Systems and methods for simulated light source positioning in rendered images

An ultrasound imaging system comprising:

• a scan converter configured to generate a three dimensional data set from ultrasound echoes received from a subject when imaging a volume of the subject;
• a volume renderer configured to calculate surface shading information of a first surface of the 3D data set based, at least in part, on a location of a simulated light source, wherein the location is within the 3D data set, and render a two dimensional projection image of the 3D data set which includes the shading information;
• and
• a user interface comprising:
• a display configured to display the 2D projection image;
• and
• an input device comprising a user interface element configured to receive first user input indicative of an in-plane position of the simulated light source within a projection plane of the 2D projection image, wherein the volume renderer is further configured, responsive to movement of the simulated light source within the 3D data set via the user input, to automatically render the simulated light source at a location corresponding to the in-plane position and a depth position determined by the volume renderer, and wherein the depth position is set such that the simulated light source maintains a set distance from the first surface within the 3D data set as the simulated light source is moved over the first surface via the user input.