Contrast-enhanced, high-resolution, susceptibility-weighted magnetic resonance imaging of the brain: dose-dependent optimization at 3 tesla and 1.5 tesla in healthy volunteers.
OBJECTIVE
We sought to determine the optimal dose of a contrast agent with known high relaxivity on 1.5 and 3 Tesla scanners that would achieve the best compromise between image quality and scan time for the clinical application of contrast-enhanced susceptibility-weighted imaging (CE-SWI).


METHODS
Pre- and postcontrast SWI was performed with different contrast agent doses (0.05, 0.1, and 0.2 mmol/kg gadobenate dimeglumine) at both 1.5 and 3 T in 6 healthy volunteers, resulting in 72 examinations. Venograms were created from minimum intensity projection reconstructions over specified deep white matter volumes to enhance the visual appearance of connected venous structures. Three independent radiologists blindly rated the visibility of the veins on a continuous scale of 1 to 10. A general linear model was used for statistical evaluation, with fixed effects of the contrast agent dose, the field strength, the rater and the patients as a random effect.


RESULTS
With CE-SWI, we found significant differences in the visibility of the deep veins dependent on the contrast media dose (P=0.02). At 3 T, the visibility of deep venous vessels, with regard to susceptibility effect, image quality, and scan time reduction after a standard contrast agent dose 0.1 mmol/kg was significantly better than that achieved with 0.05 mmol/kg. The visibility was considered equal with 0.1 mmol/kg of the contrast agent to the precontrast images and a dose of 0.2 mmol/kg. At 1.5 T, no significant difference was found between the 4 contrast agent doses. We found no difference in the visibility of the veins with the shorter sequences at 3 T compared with the sequences at 1.5 T.


CONCLUSIONS
Only a standard dose (0.1 mmol/kg) of gadobenate dimeglumine is required to achieve the optimum susceptibility effect and image quality at 3 T, together with a reduced scan time. This result can be attributed to the higher relaxivity of gadobenate dimeglumine, compared with conventional gadolinium chelates.
Department of Radiology, Osteology/Head and Neck imaging, MR Centre of Excellence, Medical Diagnostic Division, Medical University Vienna, Austria. iris.noebauer@meduniwein.ac
Iris-Melanie
IM
Noebauer-Huhmann
Katja
K
Pinker
Markus
M
Barth
Vladimir
V
Mlynarik
Ahmed
A
Ba-Ssalamah
Walter F
WF
Saringer
Michael
M
Weber
Thomas
T
Benesch
Stephan
S
Witoszynskyj
Alexander
A
Rauscher
Jürgen R
JR
Reichenbach
Siegfried
S
Trattnig
D000328:Adult; D001931:Brain Mapping / Q000379:methods*; D003287:Contrast Media / Q000008:administration & dosage* / Q000493:pharmacokinetics*; D004305:Dose-Response Relationship, Drug; D005260:Female; D019786:Gadolinium DTPA / Q000008:administration & dosage* / Q000493:pharmacokinetics*; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male
D003287:Contrast Media; D019786:Gadolinium DTPA