Magnetic Resonance Angiography of the Choroid in Patients with Age-Related Macular Degeneration

Abstract

Purpose : To evaluate significant differences in choroidal perfusion rates in patients with age-related macular degeneration (AMD) compared to age-matched control patients via magnetic resonance angiography (MRA). Techniques to understand choroidal perfusion through laser Doppler have been successfully used but are limited in the scope of measurements taken simultaneously. MRA allows for global, real-time analysis of choroidal blood flow, ensuring a more comprehensive understanding of perfusion in patients.

Methods : This prospective, observational study examined eighteen subjects aged 71 to 90 years, divided into five groups: control volunteers (12 eyes, 6 patients), mild dry (5 eyes, 3 patients), moderate dry (7 eyes, 4 patients), severe dry (6 eyes, 4 patients), and wet AMD (6 eyes, 4 patients). A non-contrast enhanced brain MRA was taken for each subject and choroidal perfusion was measured using an arterial spin labeling (ASL) technique. ASL images were co-registered with anatomical images, and then regions of interest were drawn around the choroid of each eye. To test for significant differences in blood flow, a paired t-test was used between controls and patients.

Results : Mean choroidal blood flow was significantly reduced in AMD patients when averaged together compared to controls (mean reduction [MR] of 30.6%, p<0.01). Significance was also found in mild dry (MR of 39.9%, p = 0.02), severe dry (MR of 39.2%, p=0.02), and wet AMD (MR of 31.2%, p=0.03) compared to controls. Moderate dry AMD blood flow compared to controls was not found to be significant (MR of 16.2%, p=0.18).

Conclusions : AMD patients had significantly reduced blood flow rates compared to age-matched controls when analyzed by MRA. This finding could provide important insight in AMD treatment research and demonstrates the efficacy of MRA in evaluating risk of AMD or other disorders with similar pathogeneses.

This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.

 

Fig. 1. The mean ASL image and reference image from an AMD patient (left eye: mild dry, right eye: wet) and a normal control.