Imaging method for changes in venous dynamics: a preliminary study

Abstract

The present study proposes a novel functional magnetic resonance venography (fMRV) method to examine changes in venous dynamics that are difficult to detect with commonly used MRV methods such as susceptibility-weighted imaging (SWI). We used a fast gradient echo imaging sequence, known as a time-resolved angiography with interleaved stochastic trajectories, at 7T MRI; it achieves a high temporal resolution of 3 s, which enables detection of dynamic changes in blood oxygenation within the cerebral veins. Twelve healthy individuals participated in this functional imaging study. SWI was also performed using optimized parameters for comparison with fMRV. We measured the average signal change from representative veins in the visual cortex between resting and stimulation conditions. fMRV showed signal changes between the resting and the stimulation conditions in venous vessels more clearly than SWI. Dynamic changes in venous vessel oxygenation signals were observed in the 3 s measurement windows, and these changes showed an similar to 3 s delay at the onset and offset of stimulation. The average increase in the venous signal intensity was 6.86 +/- 0.82% (mean +/- SEM) during stimulation relative to the resting condition. This study shows that fMRV can directly visualize individual venous vessel blood oxygenation changes during visual stimulation, suggesting that it could be a useful method to investigate venous dynamics induced by visual stimulation. Copyright (C) 2015 Wolters Kluwer Health, Inc. All rights reserved.