title: 3-D ultrasound imaging using a forward-looking CMUT ring array for intravascular/intracardiac applications.
abstract: Forward-viewing ring arrays can enable new applications in intravascular and intracardiac ultrasound. This work presents compelling, full-synthetic, phased-array volumetric images from a forward-viewing capacitive micromachined ultrasonic transducer (CMUT) ring array wire bonded to a custom integrated circuit front end. The CMUT ring array has a diameter of 2 mm and 64 elements each 100 microm x 100 microm in size. In conventional mode, echo signals received from a plane reflector at 5 mm had 70% fractional bandwidth around a center frequency of 8.3 MHz. In collapse mode, 69% fractional bandwidth is measured around 19 MHz. Measured signal-to-noise ratio (SNR) of the echo averaged 16 times was 29 dB for conventional operation and 35 dB for collapse mode. B-scans were generated of a target consisting of steel wires 0.3 mm in diameter to determine resolution performance. The 6 dB axial and lateral resolutions for the B-scan of the wire target are 189 microm and 0.112 radians for 8 MHz, and 78 microm and 0.051 radians for 19 MHz. A reduced firing set suitable for real-time, intravascular applications was generated and shown to produce acceptable images. Rendered three-dimensional (3-D) images of a Palmaz-Schatz stent also are shown, demonstrating that the imaging quality is sufficient for practical applications.
authors.affiliation: Edward L. Ginzton Laboratory, Stanford University, Stanford, CA, USA. dtyeh@stanford.edu
authors.forename: David T
authors.initials: DT
authors.lastname: Yeh
authors.forename: Omer
authors.initials: O
authors.lastname: Oralkan
authors.forename: Ira O
authors.initials: IO
authors.lastname: Wygant
authors.forename: Matthew
authors.initials: M
authors.lastname: O'Donnell
authors.forename: Butrus T
authors.initials: BT
authors.lastname: Khuri-Yakub
mesh_terms: D004452:Echocardiography / Q000295:instrumentation* / Q000379:methods; D019560:Echocardiography, Three-Dimensional / Q000295:instrumentation* / Q000379:methods; D004867:Equipment Design; D019544:Equipment Failure Analysis; D007089:Image Enhancement / Q000295:instrumentation* / Q000379:methods; D019047:Phantoms, Imaging; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D014159:Transducers; D018084:Ultrasonography, Interventional / Q000295:instrumentation* / Q000379:methods