1. The 2nd Affiliated Hospital, Suzhou University, Suzhou Jiangsu 215004, China;2. Department of Radiology, Suzhou Municipal Hospital, Suzhou Jiangsu 215002, China;3. The Second Affiliated Hospital of China Medical University, Shenyang 110004, China
Abstract：Objective: To evaluate the feasibility of imaging pseudotumor injected into nude mice intracranially at 1.5T MR system and to study the manifestation of MRI. Methods: Thirty nude mice were included in this study and distributed into six study groups: injecting Gd-DTPA(1μl), Gd-DTPA(2μl), Methtlene blue(1μl), Methtlene blue(2μl), mixing of Gd-DTPA and Methtlene blue(1μl), mixing of Gd-DTPA and Methtlene blue(2μl). Animals were anesthetized with thiopental sodium. After injection of corresponding reagent by using steriotatic method, the mice were transferred immediately to the MR imaging unit. Unenhanced SE and FSE images were performed with a 1.5T superconducting magnet. Signal intensity of pseudotumor and normal brain parenchyma was measured with 3 different regions of interest. Relative value(%) of enhancement was measured and compared. Volume of pseudotumor were measured and compared. Results: MR images of quite good quality were obtained in all the 30 mice. No pseudotumor was observed in the Methtlene blue(1μl) group and Methtlene blue(2μl) group. In the other groups, pseudotumor presented as focus of short T1 signals in the edge, long T1 signals in the center and short T2 signals. Relative values between pseudotumor enhancement and normal brain were different statistically in each group and there was no statistical difference in the relative value of pseudotumor across the four groups. The volume of pseudotumor was lowest in the mixing of Gd-DTPA and Methtlene blue(1μl) group than in the other groups. Conclusion: MRI is feasible in imaging nude mice brain and detect abnormal signals focus. Methtlene blue as a potential antitumor reagent had no obvious change of signal intensity of nude mice brain. The characteric signal of pseudotumor arise from the difference of the concentration of Gd-DTPA in local nude mice brain.
2006, Vol. 17 
