High-frequency-ultrasound Annular Arrays for Ophthalmic Imaging

Overview

The objective of this research is to improve the care of ocular disease and disorders, in particular the changes in the eye associated with diabetes, by providing clinicians with dramatically improved ultrasonic images of the entire eye. The research combines advanced high-frequency, high-resolution ultrasonic annular arrays transducers with new processing techniques designed to overcome several limits that have been reached with conventional high-frequency ultrasound systems. We propose that diagnosis of eye diseases using annular arrays can be more effective than the conventional ultrasound images by at least 50%; i.e., that for every 2 posterior vitreous detachments detected conventionally, 3 will be detected with the annular arrays.

In this study, we will deploy annular-array systems and assess their experimental and clinical utility for ophthalmic imaging. We hypothesize that a 20-MHz annular array will detect posterior vitreous detachment (PVD) more reliably than a conventional single element ultrasound system. Clinically, we will test the hypothesis that 20-MHz annular arrays improve detection of PVD, an important risk factor for disease progression in diabetic retinopathy. Diabetic retinopathy is the leading cause of blindness in the working population (25 to 65 years) and the third major cause of legal blindness in the U.S. We propose to carry out a study of 30 human subjects, aged 60 years or above, in whom PVD is likely to be present as a consequence of normal aging. The study will compare the ability to detect PVD using a commercial ophthalmic ultrasound system equipped with 10- and 20-MHz sector scan probes (Cinescan A/B-S, Quantel Medical), and OCT (OCT/SLO, Ophthalmic Technologies, Inc.), and the 20-MHz annular array. The annular array will be used with synthetic focusing and simulated single-element mode. The end point will be the fraction of eyes in which the PVD is visualized with each technique. This comparison is designed to demonstrate the improvement in our ability to visualize this pathologic entity using the advanced signal processing modes to be explored in this study. PVD can represent a risk factor for retinal detachment and retinal neovascularization in diabetics and localization of vitreoretinal traction points may be crucial for management. The present study, however, is limited to visualization of PVD in older normal subjects, about 75% of which would be expected to have PVD present. Thus, our aim is purely to develop an improved imaging modality rather than demonstrating its clinical efficacy in management of diabetic retinopathy or other ocular diseases. The imaging technologies that we are developing could potentially result in patents or other intellectual property, which would be managed by the Cornell Research Foundation and Riverside Research Institute. This is alluded to in the consent form for the sake of completeness.