Annular Array Ultrasound in Ophthalmology

Study Overview
=================
Brief Summary
-----------------
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. The investigators 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.

Detailed Description
-----------------
The goal of this study is to develop and evaluate advanced annular-array transducer technology for rapid, high-definition imaging. The study will assess high frequency ultrasound (HFU, 40 & 20 MegaHertz) annular arrays in 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 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. The investigators will validate system performance using animal experiments and human-subject examinations. First, in vivo animal experiments will be conducted to evaluate a 40-MegaHertz (MHz) annular array for anterior-segment imaging and a 20-MHz annular array for posterior segment and full-globe imaging. The investigators 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.

Official Title
-----------------
High-frequency-ultrasound Annular Arrays for Ophthalmic Imaging

Conditions
-----------------
Posterior Vitreous Detachment, Diabetic Retinopathy

Intervention / Treatment
-----------------
* Procedure: annular array ultrasound exam


Participation Criteria
=================
Eligibility Criteria
-----------------
Inclusion Criteria: over age 60 people with diabetic retinopathy or posterior vitreous detachments Exclusion Criteria: under age 60

Ages Eligible for Study
-----------------
Minimum Age: 60 Years
Maximum Age: 90 Years

Sexes Eligible for Study
-----------------
All

Accepts Healthy Volunteers
-----------------
Accepts Healthy Volunteers

Study Plan
=================
How is the study designed?
-----------------

Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Annular Array Ultrasound<br>Subject with possible or with known posterior vitreous detachment. Subjects with diabetic retinopathy will receive annular array ultrasound exam. | Procedure: annular array ultrasound exam<br>* For this research study you will be asked to sit in a chair. You will be given 2 drops of a numbing solution. The ultrasound camera will be enclosed in a sterile membrane and will be placed gently upon your eye. You may be asked to gaze at a light source while measurements are being made. The procedure will last about 10-15 minutes from start to finish.<br>|

What is the study measuring?
-----------------
Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Change in detection of posterior vitreous detachment: 20MHz annular array versus 10MHz single element | The investigators will examine eyes with both conventional 10MHz ultrasound and a 20MHz annular array with synthetic focusing. The investigators will evaluate and compare images acquired with both techniques and determine their relative efficacy in visualizing the presence or absence of posterior vitreous detachment. | Subjects will be examined with both the 20MHz annular array and 10MHz single element ultrasound during the same exam, approximately 30 minutes in duration. | 

 Terms related to the study
=================
Keywords Provided by Centre Hospitalier Valida
-----------------
Annular Array Ultrasound, Ultrasound Exam, Posterior Vitreous Detachment, PVD, Diabetic Retinopathy