title: Annular-ring CMUT arrays for forward-looking IVUS: transducer characterization and imaging.
abstract: In this study, a 64-element, 1.15-mm diameter annular-ring capacitive micromachined ultrasonic transducer (CMUT) array was characterized and used for forward-looking intravascular ultrasound (IVUS) imaging tests. The array was manufactured using low-temperature processes suitable for CMOS electronics integration on a single chip. The measured radiation pattern of a 43 X 140-microm2 array element depicts a 40 degrees view angle for forward-looking imaging around a 15-MHz center frequency in agreement with theoretical models. Pulse-echo measurements show a -10-dB fractional bandwidth of 104% around 17 MHz for wire targets 2.5 mm away from the array in vegetable oil. For imaging and SNR measurements, RF A-scan data sets from various targets were collected using an interconnect scheme forming a 32-element array configuration. An experimental point spread function was obtained and compared with simulated and theoretical array responses, showing good agreement. Therefore, this study demonstrates that annular-ring CMUT arrays fabricated with CMOS-compatible processes are capable of forward-looking IVUS imaging, and the developed modeling tools can be used to design improved IVUS imaging arrays.
authors.affiliation: G. W. Woodruff School of Mechanical Engineering, Georgia Institute of Technology, Atlanta, GA, USA. levent.degertekin@me.gatech.edu
authors.forename: F Levent
authors.initials: FL
authors.lastname: Degertekin
authors.forename: Rasim O
authors.initials: RO
authors.lastname: Guldiken
authors.forename: Mustafa
authors.initials: M
authors.lastname: Karaman
mesh_terms: D004867:Equipment Design; D019544:Equipment Failure Analysis; D007089:Image Enhancement / Q000295:instrumentation* / Q000379:methods; D007090:Image Interpretation, Computer-Assisted / Q000295:instrumentation* / Q000379:methods; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D014159:Transducers; D018084:Ultrasonography, Interventional / Q000295:instrumentation* / Q000379:methods