Development of estimation method for T and T values using the relaxivity of contrast agent and coagulant for a magnetic resonance imaging phantom.

The T and T values of magnetic resonance imaging phantoms used by researchers should be equivalent to those of the target tissue. However, this is difficult to achieve because of variations in the phantoms depending on the type and concentration of contrast agents and coagulants. The aim of this study was to elucidate the utility of a determination equation derived using the relaxivity of the contrast agent and coagulant. We prepared phantoms using 0.05-10 mmol L contrast agent (Gadovist; Bayer Yakuhin, Ltd., Osaka, Japan) and 0.1-5.0 wt% agar (agar, powder [010-15815]; Fujifilm Wako Pure Chemical Corporation, Osaka, Japan) and measured their T and T values. Determination equations for T and T values were derived using the relaxivity calculated from the T and T values of the contrast agent and coagulant. Subsequently, the determined values were compared with the measured values. The error rate of the determined T and T values were 7.66 ± 6.60% and 5.66 ± 4.05%, respectively, with correlation coefficients of 0.996 and 0.999. These results indicate that this method enables easy and highly accurate estimation of T and T values in MRI phantoms.