ECG-gated imaging of a mouse heart using a 40-MHz annular array

Prospective imaging with an annular-array scan system was implemented to image the mouse heart at high frame rates (> 200 frames/s, fps). M-mode data were acquired at a series of spatial locations using ECG gating. The pulse-repetition frequency of the M-mode data determined the frame rate of the final, reassembled B-mode images. The hearts of adult mice were prospectively imaged with a 40-MHz annular array. Annular-array data were acquired at an effective frame rate of 500 frames/s spanning 0.5 s. Data from the annular array were acquired for all transmit-to-receive pairs and synthetically focused in post-processing. The resulting images showed that multiple heart cycles could be clearly resolved using prospective imaging and that synthetic focusing improved the image resolution and SNR of the right ventricle, interventricular septum, posterior edge of the left ventricle (LV), and papillary muscles of the LV compared to fixed-focused imaging.