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| NOE and APT mediated MT imaging at 7.0T |
| TANG Xiang-yong, SHEN Yuan-yu, HU Wei, ZHANG Zhi-yan, DAI Zhuo-zhi, SHEN Zhi-wei, WU Ren-hua |
| Department of Medical Imaging, 2nd Affiliated Hospital, Shantou University Medical College, Shantou Guangdong 515041, China |
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Abstract Objective: Magnetization transfer(MT) imaging has recently emerged as a new and hot field for MRI in cellular and molecular imaging. Nuclear overhauser enhancement(NOE) and amide proton transfer(APT) are two special types of MT imaging. Our study is to image NOE and APT weighted MT imaging at 7.0T. Methods: Fresh egg white, bovine serum albumin(BSA), fresh lemon juice were put in tubes respectively for pre-experiment. C6 glioma cells were cultivated to plant in the rats’ right basal ganglia for making tumor models. We scanned these tubes and rats using a continuous wave pre-saturating PRESS sequence(CW-PRESS sequence). B1 was 0.6, 0.8, 1.0, 1.3, 1.6, 2.0, 3.0 μT. At the same time, we acquired rats’ MT imaging using CW-EPI sequence. The RF offset ranges from 5～-5 ppm. The parameters were set up as follows: TR 6 000 ms, TE 26.51 ms, RF duration time 4 s. Results: NOE and APT effect were obviously observed in egg white and BSA, but NOE effect wasn’t observed in lemon juice. NOE signal declined and the APT signal heightened with the increase of B1, particularly when B1<1.0 μT, NOE signal was relatively strong and APT signal was relatively small. When B1> 1.0 μT, these showed the opposite results. This tendency corresponds to that of glioma rats whose NOE signal declined and APT signal heightened. Conclusion: There must be proper parameters to acquire NOE and APT images. B1 makes a big contribution to them, even too big or too little B1 can’t get clear NOE and APT images. We firstly demonstrated the protein made contribution to NOE and APT effect and then got the decision that NOE signal declined and the APT signal heightened in glioma. Hence, we suspected that these variations were related to protein concentration.
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Received: 11 July 2017
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