The aim of this study was to evaluate magnetic resonance （MR） signal variations of transplanted human gastric adenocarcinoma cells （SGC-7901） in athymic mice after the administration of folate-receptor- targeted MR contrast agent gadolinium- diethylenetriaminepentaacetic acid-folate （Gd-DTPA-Folate）. A paramagnetic contrast agent

Gd-DTPA-Folate was synthesized by conjugating folic acid to diethylenetriaminepentaacetic acid （DTPA）

then reacting with GdCl3. The athymic mice with a human tumor cell implant were divided into either the study group or the control group. The 0.4mL Gd-DTPA-Folate was injected into the abdominal cavity of the mice in the study group

while the control group received Gd-DTPA with equivalent Gd3+. The signal features of the tumor precontrast and postcontrast were observed on TtW] MR scanning was carried out at 0

1

2

3

4

6

12 and 24 hour post-injection. The tumor signal intensity at 0

1

2 and 3h postcontrast in the study group was significantly higher than that of precontrast. The biggest difference appeared at one hour and the difference was retained about 3 hours. In the control group

there was no statistical difference between the tumor signal intensity at any time point post injection and that of prior to injection except 0 and 1h postcontrast. Gd-DTPA-Folate can produce a sustained increase in the signal intensity of the transplanted human gastric adenocarcinoma cells in athymic mice

thus

it may become a promising folate-receptor-specific magnetic resonance contrast media.