In-vivo evaluation of convex array synthetic aperture imaging

This paper presents an in-vivo study of synthetic transmit aperture (STA) imaging in comparison to conventional imaging, evaluating whether STA imaging is feasible in-vivo, and whether the image quality obtained is comparable to traditional scanned imaging in terms of penetration depth, spatial resolution, contrast resolution, and artifacts.

Acquisition was performed using our research scanner RASMUS and a 5.5 MHz convex array transducer. STA imaging was acquired using circular wave emulation by 33-element subapertures and a 20 us linear FM signal as excitation pulse. For conventional imaging a 64 element aperture was used in transmit and receive with a 1.5 cycle sinusoid excitation pulse.

Conventional and STA images were acquired interleaved ensuring that the exact same anatomical location was scanned. Image sequences were recorded in real-time and processed off-line. Seven male volunteers were scanned abdominally, and resulting images were compared by three medical doctors using randomized blinded presentation.

Penetration and image quality were scored and evaluated statistically. Results showed slightly but significantly (0.48 cm, p=0.008) increased penetration using STA. Image quality was also highly significantly (P