The goal of this study is to develop and evaluate advanced annular-array transducer technology for rapid, high-definition imaging in significant medical-research applications. The study will assess high frequency ultrasound (HFU, = 20 MHz) annular arrays in two important applications: 1) imaging microstructure in small animals (e.g., mouse embryos);and 2) imaging posterior vitreous detachments (PVDs) associated with diabetic retinopathy, the leading cause of blindness in the US working-age population according to Prevent Blindness America. Current HFU instruments do not use linear arrays for such applications because of a variety of technical and cost reasons. Instead, current HFU instruments use mechanically scanned, single-element transducers, which provide fine-resolution images over a very limited depth of field (DOF). For small-animal applications, a shallow DOF causes most anatomical boundaries in the specimen to be poorly defined;therefore, accurate micro-structural and volumetric analyses are nearly impossible. For ophthalmic applications, a shallow DOF causes most ocular anatomy to be imaged with poor definition compared to the in-focus region;therefore, because only a small portion of the eye is in focus at a given time, detection and assessment of ocular conditions such as PVD are prone to inaccuracies and false-negative determinations. Annular-array transducers offer a promising approach to significantly extend DOF and to increase the depth range over which fine-lateral resolution is provided. This proposal seeks to continue the HFU annular-array studies initiated under grant EY014371 that demonstrated the improved imaging capability of synthetically-focused annular arrays using in vivo rabbit eyes, in vivo mouse embryos, and human eye-bank eyes. The proposed project will extend those previous studies by developing and validating a real-time HFU, annular-array-based, rapid-imaging system capable of 1) dynamic-receive display imaging at a rate of >10 fps;2) data acquisition in <0.2 s for single-frame, synthetically-focused imaging;and 3) 3D data collection in <20 s. The proposed system will be modular to facilitate upgrading system components and features. We will validate system performance using animal experiments and human-subject examinations. First, in vivo animal experiments will be conducted with rabbit eyes to evaluate a 40-MHz annular array for anterior-segment imaging and a 20-MHz annular array for posterior segment and full-globe imaging. We also will utilize the 40-MHz annular array to perform in vivo 3D imaging and volumetric segmentation studies with mouse embryos. Second, we will test the hypothesis that 20-MHz annular arrays improve detection of PVD. Validation of this hypothesis will significantly improve our ability to assess disease status in diabetic retinopathy.

National Institute of Health (NIH)
National Institute of Biomedical Imaging and Bioengineering (NIBIB)
Research Project (R01)
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Biomedical Imaging Technology Study Section (BMIT)
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Lopez, Hector
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Riverside Research Institute
New York
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Chitnis, Parag V; Aristizábal, Orlando; Filoux, Erwan et al. (2016) Coherence-Weighted Synthetic Focusing Applied to Photoacoustic Imaging Using a High-Frequency Annular-Array Transducer. Ultrason Imaging 38:32-43
Aristizábal, Orlando; Mamou, Jonathan; Ketterling, Jeffrey A et al. (2013) High-throughput, high-frequency 3-D ultrasound for in utero analysis of embryonic mouse brain development. Ultrasound Med Biol 39:2321-32
Alibakhshi, Mohammad A; Kracht, Jonathan M; Cleveland, Robin O et al. (2013) Single-shot measurements of the acoustic field of an electrohydraulic lithotripter using a hydrophone array. J Acoust Soc Am 133:3176-85
Filoux, Erwan; Sampathkumar, Ashwin; Chitnis, Parag V et al. (2013) High-frequency annular array with coaxial illumination for dual-modality ultrasonic and photoacoustic imaging. Rev Sci Instrum 84:053705
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Lethiecq, Marc; Lou-Moeller, Rasmus; Ketterling, Jeffrey et al. (2012) Non-planar pad-printed thick-film focused high-frequency ultrasonic transducers for imaging and therapeutic applications. IEEE Trans Ultrason Ferroelectr Freq Control 59:1976-82
Silverman, Ronald H; Ketterling, Jeffrey A; Mamou, Jonathan et al. (2012) Pulse-encoded ultrasound imaging of the vitreous with an annular array. Ophthalmic Surg Lasers Imaging 43:82-6
Filoux, Erwan; Mamou, Jonathan; Moran, Carmel M et al. (2012) Correspondence - Characterization of the effective performance of a high-frequency annular-array-based imaging system using anechoic-pipe phantoms. IEEE Trans Ultrason Ferroelectr Freq Control 59:2825-30
Filoux, Erwan; Mamou, Jonathan; Aristizabal, Orlando et al. (2011) Characterization of the spatial resolution of different high-frequency imaging systems using a novel anechoic-sphere phantom. IEEE Trans Ultrason Ferroelectr Freq Control 58:994-1005
Ketterling, Jeffrey A; Aristizábal, Orlando (2009) Prospective ECG-gated mouse cardiac imaging with a 34-MHz annular array transducer. IEEE Trans Ultrason Ferroelectr Freq Control 56:1394-404

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