Caffeine-induced Vascular Reactivity in the Ophthalmic Artery : A Preliminary Study using Phase-contrast MR Angiography

Abstract

Present study assesses vascular reactivity of the ophthalmic artery (OA) in the caffeine presence using magnetic resonance (MR) imaging technique, and it was compared with those of intracranial vessels, such as the middle cerebral and internal carotid arteries. All subjects underwent two MR scans in pre- and post-caffeine consumption conditions. Each scan included two imaging data sets, obtained using conventional time-of-flight (TOF) and phase-contrast (PC) MR angiography (MRA) to examine the signal changes of the target cerebral vessels and measure their velocities in 3 Tesla (3T) MRI, respectively. TOF MRA delineates the detail of the OA more clearly in post-caffeine condition, although it was also visualized in pre-caffeine. PC MRA can quantitatively measure changes in the blood flow velocity of OA. In conclusion, this study shows that MR imaging modality, especially PC MRA, can be used to quantify blood flow velocity in the OA, following a caffeineinduced blood flow increase.