Volumetric real-time imaging using a CMUT ring array.
A ring array provides a very suitable geometry for forward-looking volumetric intracardiac and intravascular ultrasound imaging. We fabricated an annular 64-element capacitive micromachined ultrasonic transducer (CMUT) array featuring a 10-MHz operating frequency and a 1.27-mm outer radius. A custom software suite was developed to run on a PC-based imaging system for real-time imaging using this device. This paper presents simulated and experimental imaging results for the described CMUT ring array. Three different imaging methods--flash, classic phased array (CPA), and synthetic phased array (SPA)--were used in the study. For SPA imaging, two techniques to improve the image quality--Hadamard coding and aperture weighting--were also applied. The results show that SPA with Hadamard coding and aperture weighting is a good option for ring-array imaging. Compared with CPA, it achieves better image resolution and comparable signal-to-noise ratio at a much faster image acquisition rate. Using this method, a fast frame rate of up to 463 volumes per second is achievable if limited only by the ultrasound time of flight; with the described system we reconstructed three cross-sectional images in real-time at 10 frames per second, which was limited by the computation time in synthetic beamforming.
Edward L. Ginzton Laboratory, Stanford University, Stanford, CA, USA. choejw@stanford.edu
Jung Woo
JW
Choe
Ömer
Ö
Oralkan
Amin
A
Nikoozadeh
Mustafa
M
Gencel
Douglas N
DN
Stephens
Matthew
M
O'Donnell
David J
DJ
Sahn
Butrus T
BT
Khuri-Yakub
D000818:Animals; D002645:Chickens; D003198:Computer Simulation; D004452:Echocardiography; D004867:Equipment Design; D007091:Image Processing, Computer-Assisted / Q000379:methods*; D019047:Phantoms, Imaging; D059629:Signal-To-Noise Ratio; D014159:Transducers; D014463:Ultrasonography / Q000295:instrumentation*