Improved Vessel Delineation in Keyhole Time- Resolved Contrast-Enhanced MR Angiography Using a Gadolinium Doped Flush

Abstract

Purpose: To prospectively assess the influence of a gado- linium 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. Materials and Methods: Twenty-two patients scheduled for contrast-enhanced craniocerebral MRI underwent a supplemental 4D CE-MRA covering the carotids to the su- perior 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 con- trast-to-noise (CNR) ratios over time were compared. Results: Both vessel delineation (internal carotid artery [ICA]: slopesaline 308.5; slopeGd 528.9; P 0.006; su- perior sagittal sinus [SSS]: slopesaline 505.3; slopeGd 674.9; P 0.007) and CNR (ICA: CNRsaline 57.3; CNRGd 80.55; P 0.0417; SSS: CNRsaline 74.15; CNR Gd 117.4; P 0.0331) of the ICA and SSS were significantly increased using the gadolinium doped flush. Conclusion: A low concentrated gadolinium flush in com- parison to a pure saline flush improves significantly vessel contrast and their delineation in time-resolved CE-MRA using the keyhole technique. © 2009.