Fig. 3.
The scanning protocol. A T2 weighted image (T2WI) was obtained to detect the cerebral aqueduct. Next, phase contrast-magnetic resonance imaging (PC-MRI) was performed at rest (release) to measure VRrelease0. The absence of signals in the jugular veins after compression was confirmed with the acquisition of phase contrast-magnetic resonance imaging with compression, a steady-state free precession sequence (FIESTA). After 60 seconds of compression, a PC-MRI scan was performed (push 1). The compression was then released and PC-MRI images were obtained at 5, 40, and 75 seconds after the release (release 1-1, release 1-2, and release 1-3). After a 60-second, the procedure was repeated to obtain a second set of measurements (push 2, release 2-1, release 2-2, and release 2-3).