Imaging latency of Golden Angle 2D MRI using real-time GPU-accelerated image reconstruction for MR-guided radiotherapy

For tumor tracking in MRI-guided radiotherapy it is important to minimize the latency between the moment of anatomic change and its appearance on the MR image. By using a 2D golden angle sampling trajectory in combination with a sliding window reconstruction, the latency can be decoupled from the frame rate, yielding frame rates of up to one repetition time. We implemented a real-time GPU-accelerated reconstruction pipeline where k-space data is directly streamed to a reconstruction server during acquisition. Using this we investigated the influence of the sliding window width on the latency, reconstruction time, frame rate and image quality.