Where Contrast Agent Concentration Really Matters – A Comparison of CT and MRI

Abstract

Contrast agent concentration is a key parameter for the optimization of dynamic imaging techniques such as angiography or perfusion in CT, whereas in dynamic MRI, contrast agent dose and relaxivities are the leading parameters.

Does Higher Gadolinium Concentration Play a Role in the Morphologic Assessment of Brain Tumors? Results of a Multicenter Intraindividual Crossover Comparison of Gadobutrol versus Gadobenate Dimeglumine (the MERIT Study)

“…20,37 Thus, 3 blinded readers found no relevant benefit for the more highly concentrated gadobutrol in terms of lesion conspicuity, visualization, or sensitivity for detection. Rather, our intraindividual comparison of gadobenate dimeglumine and gadobutrol at an identical dose of 0.1 mmol/kg of body weight confirms that significantly improved qualitative and quantitative enhancement of brain tumors is achieved with gadobenate dimeglumine without any difference in safety.…”

Effectiveness of a high relaxivity contrast agent administered at half dose in dynamic susceptibility contrast MRI of brain gliomas

“…This observation is in accordance with the findings of Thilmann et al, who also found identical contrast bolus shapes measured as FWHM after fast injection of 0.1 and 0.2 mmol/kg bw of the 1.0 M agent gadobutrol and 0.1 mmol/kg bw of the 0.5 M agent gadobenate. If very short (<5 sec) contrast agent injection times are used, a lower contrast volume with additional reduction of the injection time does not result in a more compact bolus shape in the arterial vessels or tissues because the final bolus shape in the ROI is determined by physiologic bolus‐widening effects occurring during the passage of the bolus through the body . For conventional brain tumor imaging the r1 relaxivity of the GBCA is the most important factor for contrast enhancement on T 1 ‐weighted images.…”

Are There Differences between Macrocyclic Gadolinium Contrast Agents for Brain Tumor Imaging? Results of a Multicenter Intraindividual Crossover Comparison of Gadobutrol with Gadoteridol (the TRUTH Study)

“…This conclusion is not unexpected, given that image acquisition for morphologic imaging of brain tumors typically begins at least 3-5 minutes following contrast administration, by which time contrast equilibration will have occurred, which would obviate any potential benefits of a higher administered concentration. 12,13 Second, although r1 relaxivity is a major factor for contrast efficacy, 13 the slightly different r1 relaxivity values for gadobutrol and gadoteridol are insufficient to show any discernable clinical effect, either for qualitative or quantitative lesion enhancement or for diagnostic performance.…”