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G.L. Trick, J. Liggett, J. Levy, I. Adamsons, P. Edwards, U. Desai, B.A. Berkowitz; Dynamic Contrast Enhanced MRI Studies of Diabetic Macular Edema . Invest. Ophthalmol. Vis. Sci. 2003;44(13):3960.
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© ARVO (1962-2015); The Authors (2016-present)
Purpose: In this study, we evaluated the use of dynamic, contrast enhanced MRI (DCE-MRI) to measure the blood retinal barrier permeability surface area product (BRB PS) in diabetic macular edema. Methods: In a methodology study, 10 control subjects (4 M (42-52 years of age.), 6 F (33-50 years of age)) and 3 patients with clinically significant macular edema 1 M (72 years of age), 2 F (64 – 68 years of age) were studied. Examinations of additional patients with diabetic macular edema are ongoing. The BRB PS (cm3/min) was measured using DCE-MRI. Subjects were asked to refrain from blinking during a 12-s fast low-angle shot (FLASH) image, and to blink if needed during the following 3-s rest period. This sequence was repeated 20-40 times (5-10 min image acquisition) and used to generate high resolution (390 x 390 µm2 in-plane) eye images which were free of eye movement artifacts. Two image sets were collected before contrast agent (Gd-DTPA) and two to four image sets were collected after Gd-DTPA injection. Signal intensity changes in the vitreous due to leakage of Gd-DTPA into the retina were converted to BRB PS. PS values in all groups were adjusted for potential contamination from signal intensity changes in the ocular muscles (due to partial volume effects and motion) as well as for incoherent baseline noise as measured in the controls. Results: The DCE-MRI procedure was well tolerated by all subjects. No BRB-specific leakage of contrast agent was detected in any of the control subjects. Consequently, the calculated BRB PS in control subjects was 0 cm3/min. Leakage was detected in all 3 diabetic patients. This leakage was localized to the macular region with an average BRB PS of 1.15 + 0.4 x 10-5 cm3/min (mean + SEM). Conclusions: DCE-MRI provides a non-invasive, real-time "snap shot" of BRB PS that is expected to provide a useful metric for quantitative staging of drug treatment effects in humans with diabetic macular edema.
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