The ability to measure normal BBB leakage in individual subjects would provide a technique to quantify extremely subtle BBB abnormalities in neurological disease. The technique is extremely demanding of scanner stability and vulnerable to low-level (invisible) artefacts. In phantom and healthy control scans without Gd machine stability is good when using Ernst-angle scanning. Image artefact currently limits precision in measuring BBB permeability, and is probably caused by pulsatile motion of the Superior Sagittal Sinus (SSS). Image noise is insignificant when optimised imaging parameters (e.g. FA=30o, TR=30ms) are used. Blood signal is significant and can probably be modelled using SSS signal.