Maximum Relationship between Contrast Agent Concentration and Signal Intensity in 0.3 T and 1.5 T using T1-weighted Spin Echo Sequence

Determination of maximum injected contrast agent leading to maximum signal intensity (SI) is of great importance in magnetic resonance imaging (MRI). Different parameters including strength of the magnetic filed in MRI, used sequences, and imaging factors play role in an increase in SI. The aims of this study were to investigate the maximum relationship between concentration of contrast agent and SI on T1-weighted image in 0.3 T and 1.5 T MRI scanners by use of sine echo sequence. A water-filled phantom containing vials of different concentrations of Gd-DTPA (0 to 19.77mmol/L) was used. Mean SI was obtained in region of interest using T1-weighted images. Clinical standard head coil was used in this study. Coil non-uniformity was corrected on SI. Maximum SI can be seen at concentration of 5.95 and 4.96 mmol/L for 0.3 T and 1.5 T, respectively. In addition, the maximum linear relationship between contrast agent concentration and SI were 2.02 and 2.70 mmol/L for 0.3 T and 1.5 T, respectively. Maximum SI can be seen at concentration of 5.95 and 4.96 mmol/L for 0.3 T and 1.5 T, respectively. In addition, the maximum linear relationship between contrast agent concentration and SI were 2.02 and 2.70 mmol/L for 0.3 T and 1.5 T, respectively. This study showed that magnetic field strength might have effect on the relationship between maximum contrast agent concentration and SI.