Algorithms for real-time FastHARP cardiac function analysis

FastHARP is a magnetic resonance pulse sequence that can acquire tagged cardiac images at 40 ms per frame. Data from just two heartbeats can be used to compute in-plane quantities using the harmonic phase (HARP) method for describing myocardial deformation, such as circumferential and radial strain. Although HARP computations have previously been coded to keep pace with the FastHARP pulse sequence, further computational speed improvements are necessary in order to achieve either smoother strain images using view-sharing concepts or more tracked points for more detailed strain analysis. In this work, we present faster processing routines that allow improved temporal resolution and more detailed real-time tracking and analysis. With this code, HARP strain computations can now be computed and displayed in real-time after a one heartbeat delay with a temporal interval of 20 ms.