title: Pulse-encoded ultrasound imaging of the vitreous with an annular array.
abstract: The vitreous body is nearly transparent both optically and ultrasonically. Conventional 10- to 12-MHz diagnostic ultrasound can detect vitreous inhomogeneities at high gain settings, but has limited resolution and sensitivity, especially outside the fixed focal zone near the retina. To improve visualization of faint intravitreal fluid/gel interfaces, the authors fabricated a spherically curved 20-MHz five-element annular array ultrasound transducer, implemented a synthetic-focusing algorithm to extend the depth-of-field, and used a pulse-encoding strategy to increase sensitivity. The authors evaluated a human subject with a recent posterior vitreous detachment and compared the annular array with conventional 10-MHz ultrasound and spectral-domain optical coherence tomography. With synthetic focusing and chirp pulse-encoding, the array allowed visualization of the formed and fluid components of the vitreous with improved sensitivity and resolution compared with the conventional B-scan. Although optical coherence tomography allowed assessment of the posterior vitreoretinal interface, the ultrasound array allowed evaluation of the entire vitreous body.
authors: Department of Ophthalmology, Columbia University Medical Center, New York, NY 10032, USA. rs3072@columbia.edu
authors: Ronald H
authors: RH
authors: Silverman
authors: Jeffrey A
authors: JA
authors: Ketterling
authors: Jonathan
authors: J
authors: Mamou
authors: Harriet O
authors: HO
authors: Lloyd
authors: Erwan
authors: E
authors: Filoux
authors: D Jackson
authors: DJ
authors: Coleman
mesh_terms: D000465:Algorithms; D003941:Diagnostic Techniques, Ophthalmological / Q000295:instrumentation*; D004867:Equipment Design; D006801:Humans; D008297:Male; D008875:Middle Aged; D041623:Tomography, Optical Coherence; D014159:Transducers; D014463:Ultrasonography / Q000295:instrumentation*; D014822:Vitreous Body / Q000000981:diagnostic imaging*; D020255:Vitreous Detachment / Q000000981:diagnostic imaging*