A phase-based motion estimation technique for mouse cardiac function using monogenic signal and high resolution ultrasound

Regional tissue motion estimation using medical ultrasound images is an important first step in solving many problems with significant clinical applications that include non-invasive assessments of myocardial function in echocardiography. Many existing techniques for estimating motion are based on block-matching using B-mode image intensity, and phase information is often neglected. In digital image processing, it is widely accepted that the information carried in the image phase is more important than information carried by its amplitude. In this work, we implemented a phase-based tracking technique using the monogenic signal to estimate cardiac motion in both synthetic and in vivo mouse heart data. In vivo mouse heart data were acquired with a 30MHz transducer array and synthetic data were simulated with Field II using comparable parameters. The tracking results were compared with a reference speckle tracking analysis method: minimum sum of absolute different (MSAD). The tracking errors for in vivo mouse heart data were 5.3±1.6% and 7.1±2.1% for phase-based and MSAD, respectively. Phase-based displacement estimation via monogenic signal is an improved alternative to conventional block-matching techniques as it makes use of image signal phase information. Phase-based motion tracking using the monogenic signal is accurate and computationally inexpensive.