Difference of T1-weighted contrast among various pulse sequences. Basic study by using a phantom containing Gd-DTPA solutions

In order to select the optimal pulse sequence in an abdominal contrast-enhanced MR examination, we have investigated signal intensity characteristics of various T1-weighted pulse sequences by using sample tubes containing a variety of concentration of Gd-DTPA solution ranging from 0.1 to 40 mmol/l. T1-weighted pulse sequences including spin echo (SE), turbo spin echo (TSE), gradient and spin echo (GRASE), non-spoiled fast field echo (FFE), spoiled fast field echo (T1FFE) and spoiled turbo field echo (T1TFE) were included in this study. All images were obtained with a 1.5 T superconductive MR unit. Signal intensity for each Gd-DTPA solution was measured. Contrast ratios and signal-to-noise ratios were calculated and compared among those pulse sequences. 3D-T1FFE showed the highest contrast ratio and signal intensity at the high concentrations of Gd-DTPA solution over 1 mmol/l, which suggest that 3D-T1FFE could be best suited for contrast-enhanced MR angiography. SE and TSE sequences were superior to gradient echo sequences such as T1FFE and T1TFE in signal intensity at the low concentrations of Gd-DTPA solution ranging between 0.1 mmol/l and 0.8 mmol/l, which suggested that SE and TSE could be better used in detection of lesions with subtle contrast enhancement. In conclusion, knowledge of signal intensity characteristics of various pulse sequences is important to select a pulse sequence suitable for an abdominal contrast-enhanced MR examination in a variety of clinical settings. (author)