Preparation and animal experimental study in MRI contrast agent Gd-DTPA-DG

Objective To synthesize a paramagnetic deoxy-glucose-type MR contrast agent diethylenetriamine pentaacetic acid-gadolinium salt deoxy-glucose(Gd-DTPA-DG) and to study the tumor signal intensity pattern in vivo MR imang in tumor-bearing nude mice model.Methods After successfully synthesized diethylenetriamine pentaacetic acid glucosamine(DTPA-DG),Gd2O3 was added to conjugate with it,and Gd-DTPA-DG,an MR contrast agent,was thus preparated.We conducted in vitro studies using nude mice with transplanted human adenocarcinoma of lung as experimental model.The mice were divided into study group(n=10) and control group(n=10).The animals in the experimental group were injected with Gd-DTPA-DG via vena caudalis,whereas the routine Gd-DTPA was used in the control group at the same dosage of gadolinium with the same amount of 0.1 mmol/kg as the experimental group.The tumor signal intensities(SI) on T1W1 was measured at 30 s,2 min,5 min,10 min,20 min,30 min,45 min,1 h,2 h respectively after injection of contrast agents with SI of the anterior limb muscles on the same side as control.Then all of the results were statistically analyzed.The CNR(contrast to noise ratio) was calculated as wel1.Results Gd-DTPA-DG compared with Gd-DTPA in tumor tissue showed a stronger and more durable reinforced.Consequently,there was no statistically significant difference on the SI in the experimental group before and after injection of the specific contrast agents at 30 s(P=0.171).In comparison with the pre-contrast imaging,SI of tumor and musc1es in the experimental group increased greatly at 30 min after injection of Gd-DTPA-DG with significant difference(P0.001).In control group,there was statistically significant difference on SI before and after injection of Gd-DTPA at 5 min(P0.001),and the contrast in the tumors almost entirely washed out at 2 h after injection of Gd-DTPA(P=0.28).Conclusion Gd-DTPA-DG can produce a greatly signal intensity enhancement of the transplanted human adenocarcinoma of lung in nude mice.It will be a newly type of paramagnetic Gd(Ⅲ) MR contrast agent..