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Multielement synthetic transmit aperture imaging using temporal encoding

2003; Institute of Electrical and Electronics Engineers; Volume: 22; Issue: 4 Linguagem: Inglês

10.1109/tmi.2003.809088

1558-254X

K.L. Gammelmark, Jørgen Arendt Jensen,

Microwave Imaging and Scattering Analysis

A new method to increase the signal-to-noise ratio (SNR) of synthetic transmit aperture imaging is investigated.The approach utilizes multiple elements to emulate a spherical wave, and the conventional short excitation pulse is replaced by a linear frequency-modulated (FM) signal.The approach is evaluated in terms of image quality parameters in comparison to linear array imaging.Field II simulations using an 8.5-MHz linear array transducer with 128 elements show an improvement in lateral resolution of up to 30% and up to 10.75% improvement in contrast resolution for the new approach.Measurements are performed using our experimental multichannel ultrasound scanning system, RASMUS.The designed linear FM signal obtains temporal sidelobes below 55 dB, and SNR investigations show improvements of 4-12 dB.A 30 mm ( 45%) increase in penetration depth is obtained on a multitarget phantom with 0.5 dB/[cm MHz] attenuation.Furthermore, in vivo images of the abdomen are presented, which demonstrate the clinical application of the new approach.