Improved vessel delineation in keyhole time-resolved contrast-enhanced MR angiography using a gadolinium doped flush

To prospectively assess the influence of a gadolinium doped saline flush compared with a pure saline flush on the image quality of the supra-aortic vessels using time-resolved contrast-enhanced MR angiography (4D CE-MRA) in a randomized double blind clinical trial.

Twenty-two patients scheduled for contrast-enhanced craniocerebral MRI underwent a supplemental 4D CE-MRA covering the carotids to the superior sinus consisting of 30 dynamics of a T1-weighted 3D gradient-echo sequence (FFE) in sagittal direction. The temporal resolution of 1.1 s per dataset was achieved using the keyhole technique with the reference scan acquired at the end. Immediately after the intravenous (IV) injection of 0.1 mmol Gd/kg body weight of gadoterate, our patients received a 50-mL flush consisting either of a 0.9% saline solution (n = 11) or doped with 50 mM gadolinium (n = 11; total Gd: 0.11 mmol/kg) at a flow-rate of 2 mL/s. Vessel delineation, image quality, signal-to-noise- (SNR) and contrast-to-noise (CNR) ratios over time were compared.

Both vessel delineation (internal carotid artery [ICA]: slope(saline) = 308.5; slope(Gd) = 528.9; P = 0.006; superior sagittal sinus [SSS]: slope(saline) = 505.3; slope(Gd) = 674.9; P = 0.007) and CNR (ICA: CNR(saline) = 57.3; CNR(Gd) = 80.55; P = 0.0417; SSS: CNR(saline) = 74.15; CNR(Gd) = 117.4; P = 0.0331) of the ICA and SSS were significantly increased using the gadolinium doped flush.

A low concentrated gadolinium flush in comparison to a pure saline flush improves significantly vessel contrast and their delineation in time-resolved CE-MRA using the keyhole technique.