## Materials and Methods
### Method of Analysis  
The Medical Standard's PACSPLUS program was used to measure SI in both the phantom and clinical studies. Regions of interest (ROIs), depicted as a green ellipse (Area = 4.5 cm\({}^{2}\), 650 px) in Figure 3b, were selected in the cross-section of containers with different GBCA concentrations, and the mean SI was measured for each container. In order to quantitatively analyze the degree of enhancement according to the TE change in the phantom study, the following nine evaluation criteria were set: (1) the saline signal intensity of phantom study (SSI\({}^{1}\)), which is similar to free water in the body; (2) the fat signal intensity of the phantom study (FSI\({}^{1}\)); (3) the contrast percentage of fat to saline (CPFS) was calculated as the contrast between SSI\({}^{1}\) and FSI\({}^{1}\), expressed as a percentage; (4) the response start point (RSP) was the point at which signal enhancement could be observed with the naked eye (SI \(\geq\) 40 a.u.); (5) the max peak signal intensity (MPSI) was the highest SI; (6) the max peak point (MPP) was the point at which the MPSI was detected; (7) the enhancement percentage of MPSI to saline (EPMS) was the signal enhancement of the MPSI relative to free water; (8) the enhancement percentage for each mol (EP mmol) was the signal enhancement for each GBCA concentration; and (9) the average of SI for each mol per TE (AST) was the mean SI across all concentrations at each TE. Here, CPFS, EPMS, and EP were calculated by the following Formulas (2)-(4):  
\[\text{CPFS}=\left((\text{FSI}-\text{SSI})/\text{SSI}\right)\times 100 \tag{2}\]  
\[\text{EPMS}=\left(\text{MPSI}-\text{SSI}\right)\times 100 \tag{3}\]  
\[\text{EP}=\left((\text{SI on each mmol}-\text{SI on previous mmol})/\text{SI on previous mmol}\right)\times 100 \tag{4}\]  
In the clinical study, the following nine quantitative criteria were established to compare the contrast between the extent of enhancement and brain parenchyma according to TE changes: (1) the saline signal intensity of the clinical study (SSI\({}^{2}\)) was the SI of saline in the clinical phantom; (2) the fat signal intensity of clinical study (FSI\({}^{2}\)) was the SI of fat in the 2 nd phantom; (3) the SC was the SI of the intraventricular CSF; (4) the SBP was the SI of brain parenchyma; (5) the average SI by TE for each molar concentration (ASTM) was the SI for each TE averaged across all molar concentrations; (6) the enhancement percentage of the SI for each mol by SBP (EPSS of each mol) was calculated as the contrast between the SBP and the GBCA SI at each concentration, expressed as percentages; (7) the AEPSS was the average of EPSS; (8) the enhancement percentage of SI for each mol by SC (EPSC  
Figure 3: Images of the clinical study, (**a**,**b**) clinical phantom design and photographs; (**c**,**d**) the setup of the clinical study.  
of each mol) was calculated as the contrast between the SC and the GBCA SI at each concentration, expressed as percentages; and (9) the AEPSC was the average of EPSC. Here, the EPSS and EPSC were calculated by the following formulas (5) and (6):  
\[\text{EPSS}=((\text{SI on each mmol}-\text{SBP})/\text{SBP})\times 100 \tag{5}\]  
\[\text{EPSC}=((\text{SI on each mol}-\text{SC})/\text{SC})\times 100 \tag{6}\]