High frame rate three-dimensional (3D) ultrasound imaging would offer excellent possibilities for the accurate assessment of carotid artery diseases. This calls for a matrix transducer with a large aperture and a vast number of elements. Such a matrix transducer should be interfaced with an application-specific integrated circuit (ASIC) for channel reduction. However, the fabrication of such a transducer integrated with one very large ASIC is very challenging and expensive. In this study, we develop a prototype matrix transducer mounted on top of multiple identical ASICs in a tiled configuration. The matrix was designed to have 7680 piezoelectric elements with a pitch of 300 μm × 150 μm integrated with an array of 8 × 1 tiled ASICs. The performance of the prototype is characterized by a series of measurements. The transducer exhibits a uniform behavior with the majority of the elements working within the −6 dB sensitivity range. In transmit, the individual elements show a center frequency of 7.5 MHz, a −6 dB bandwidth of 45%, and a transmit efficiency of 30 Pa/V at 200 mm. In receive, the dynamic range is 81 dB, and the minimum detectable pressure is 60 Pa per element. To demonstrate the imaging capabilities, we acquired 3D images using a commercial wire phantom.

To accurately investigate the state of the carotid artery by the local haemodynamics and motion of the plaque using ultrasound, high-frame rate volumetric imaging is necessary. We have specifically designed a matrix array for this purpose. In this proceeding we will focus on imaging a volumetric flow profile using this matrix. For this purpose, we extend a fast frequency domain vector flow imaging method to 3D and perform measurements on a flow phantom. The results indicate that it is feasible to estimate 3D velocity vectors on a 3D grid using our matrix transducer and the proposed algorithm.