FIG 2. MR signal time course correlation with contrast-enhanced T1-weighted scans and phase-contrast MR angiography (S5). Contrast-enhanced studies reliably show sulcal and superficial veins, whereas the phase-contrast MR angiography with given flow sensitivity demonstrates vessels the size of large bridging veins. Significant change in MR signal (
S) is seen in bridging veins even close to superior sagittal sinus. From this data, one can presume that dilution of increased oxyhemoglobin content and therefore decay of S takes place when bridging veins enter large draining sinuses. Arrows point at sulcal veins, arrowheads at large bridging veins.
