GPU volume rendering in 3D echocardiography: Real-time pre-processing and ray-casting

Since real-time acquisition of 3D echocardiographic data is achievable in practice, many volume rendering algorithms have been proposed for visualization purposes. However, due to the large amounts of data and computations involved a trade-off between image quality and computational efficiency has to be made. The main goal of our study was to generate high quality volume renderings in real-time, by implementing pre-processing and ray-casting algorithms directly on the GPU. Furthermore the advantage of combining a-priori anatomic and functional information with the volume rendered image was also investigated. The proposed algorithms were implemented both in CUDA and OpenCL and validated on patient datasets acquired using a GE Vivid7 Dimensions system. Assuming a 512×512 pixels output resolution, average running times of 4.2 ms/frame are achievable on high-end graphics systems. Furthermore a good correspondence between wall thickening and segmental longitudinal strain values was visually observed. By implementing ray-casting on the GPU, the overall processing time is significantly reduced, thus making real-time interactive 3D volume rendering feasible. Combining anatomical and functional information allows for a quick visual assessment of a given case.