ABSTRACT
Diabetic retinopathy is one of the leading causes of blindness in the United States today. Because early treatment of proliferative retinopathy offers the best chance for visual salvation, there is an essential need for methods of identifying eyes at high risk. Recent research has shown that subclinical leakage from retinal blood vessels is one of the earliest signs of retinopathy. The feasibility of using radionuclide techniques to quantitate blood-retinal barrier disruption is demonstrated by a study in which 23 diabetics and 7 nondiabetics were imaged with an Anger camera in the anterior Waters projection at 2 hours after the administration of Tc-99m DTPA. In the digitized images, regions of interest were placed over each orbit and over one of the cerebral hemispheres. Orbital counts were then compared to cerebral counts on a per pixel basis. Eye to brain ratios were found to be lowest for nondiabetics and highest for patients with proliferative retinopathy. Additionally, the dynamic analysis of the same radiopharmaceutical may allow investigators to further study the pathophysiology of the diabetic eye.
Subject(s)
Diabetes Mellitus/diagnostic imaging , Diabetic Retinopathy/diagnostic imaging , Eye/blood supply , Adult , Aged , Diabetes Mellitus, Type 1/diagnostic imaging , Eye/diagnostic imaging , Humans , Middle Aged , Pentetic Acid , Radionuclide Imaging , Technetium , Technetium Tc 99m PentetateABSTRACT
A computerized radiotracer technique for the detection of loss of retinal vascular integrity secondary to diabetes is presented. Radionuclide retinal scintigraphy with Technetium-99m DTPA was performed on 40 insulin-dependent diabetics and 10 nondiabetics. A ratio of eye to brain activity was used to eliminate errors associated with absolute counting. Ratios were found to be significantly higher in diabetics, especially those with active neovascularization. This technique may prove useful in the assessment and staging of eyes prone to retinopathy.
