Multielement synthetic transmit aperture imaging using temporal encoding.
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 (approximately 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.
Gammelmark
Kim Løkke
KL
Center for Fast Ultrasound Imaging, Orsted, DTU, Building 348, Technical University of Denmark, 2800 Kgs. Lyngby, Denmark. klg@oersted.dtu.dk
Jensen
Jorgen Arendt
JA
D000005:Abdomen / Q000000981:diagnostic imaging; D000328:Adult; D000465:Algorithms; D016477:Artifacts; D003198:Computer Simulation; D003560:Cysts / Q000000981:diagnostic imaging; D004867:Equipment Design; D006801:Humans; D007089:Image Enhancement / Q000295:instrumentation* / Q000379:methods*; D008297:Male; D008954:Models, Biological; D009038:Motion; D019047:Phantoms, Imaging; D011786:Quality Control; D015203:Reproducibility of Results; D012542:Scattering, Radiation; D012680:Sensitivity and Specificity; D014463:Ultrasonography / Q000295:instrumentation* / Q000379:methods*