Real-time visualization of 4D cardiac MR images using graphics processing units

Real-time display of dynamic three-dimensional (3D) cardiac images has important applications in minimally invasive image-guided cardiac surgery and therapy. However, in practice, the high computational cost usually prohibits its application in a real-time medical environment, or else the low image quality does not satisfy the clinical requirements. Surface based organ models or orthogonal image planes are often employed instead, but in the process important intra cardiac data are lost, and intuitive spatial anatomical relationships are eliminated. In this paper, we take advantage of the programmability, parallelism and increased computational precision of modern graphics processing units (GPUs) to build a ray casting based real-time 3D rendering engine, directly running on the graphics vertex and fragment processors. This approach provides enhanced image quality similar to software-based implementations, but its rendering speed is competitive with the traditional but inferior quality slice based volume rendering approaches. In addition, we propose a new dynamic volume texture binding technique, and embedded it into our 3D rendering engine to permit visualize the 4D MR cardiac dataset in real-time