Altered Blood Flow in the Ophthalmic and Internal Carotid Arteries in Patients with Age-Related Macular Degeneration Measured Using Noncontrast MR Angiography at 7T

Analysis procedure for correcting EC bias and defining the vessel ROI. A, A PC-MRA magnitude image is used to place a 12-mm-diameter ROI for EC correction in vessel-free tissue adjacent to the vessel ROI (blue). The red line in the inset TOF image indicates the PC-MRA slice position. The vessel ROI (yellow) is shown within the yellow box, which depicts the region enlarged in B and C. Enlarged PC-MRA magnitude images show the vessel cross-section alone (B) and with the vessel ROI superimposed (C). D, Time-series of EC-corrected flow data in units of centimeters/second from 1 example PC-MRA acquisition with a single VENC value in 1 subject.

Boxplots of unnormalized flow velocities (A and B) and volumetric flow rates (C and D) in the OAs (A and C) and ICAs (B and D). Vessels were divided into 4 groups: healthy controls, early AMD, intermediate AMD, and late AMD. The asterisk signifies P < .05 compared with controls.

Linear trend test plot, which demonstrates that the rate of decline in OA volumetric flow with disease progression is statistically significant.

Boxplots of flow velocity (A) and volumetric flow (B) in the OA normalized to upstream ICA flow rates. Normalized flow values represent the OA flow as a ratio of ICA flow. Vessels are divided into 4 groups: healthy controls, early AMD, intermediate AMD, and late AMD. The asterisk signifies P < .05 compared with controls.