Enhancement Effects and Relaxivities of Gadolinium-DTPA at 1.5 versus 3 Tesla: A Phantom Study

抄録

Purpose: To investigate the difference in enhancement effects and relaxivities of the gadolinium chelate at 1.5 and 3 Tesla (T) and to elucidate the contribution of the high magnetic field to contrast enhancement in spin-echo (SE) and gradient-echo (GRE) images.
Methods: Phantoms containing water with or without gadopentetate dimeglumine (Gd-DTPA) at different concentrations were scanned using 1.5T and 3T MRI scanners of the same manufacturer and under the same temperature conditions and scanning parameters. Relaxivities of gadolinium, R₁ and R₂, were estimated from serial T₁ and T₂ values of the phantoms using linear regression. Contrast enhancement ratios in SE and GRE T₁-weighted images were compared at 1.5 and 3T.
Results: The R₁ and R₂ of Gd-DTPA at 1.5 and 3T were 4.79 and 5.14, and 4.50 and 5.09, respectively. Although the relaxivities at 3T were slightly lower than those at 1.5T, the contrast enhancement ratio improved in both SE and GRE images as a result of T₁ prolongation of the water at 3T.
Conclusion: The decrease in relaxivities of the Gd-DTPA at 3T appears to be so small that T₁ prolongation of the water improves contrast enhancement, suggesting a potential clinical advantage in administration of Gd-DTPA at high field strength.