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. Author manuscript; available in PMC: 2015 Oct 21.
Published in final edited form as: Magn Reson Med. 2015 Apr 27;74(2):544–549. doi: 10.1002/mrm.25748

FIG. 3.

FIG. 3

PEG-3 promoter:LRP exhibited CEST contrast in a murine model of rat 9L glioma. Representative T2-weighted (a,c) and CEST images superimposed on T2-weighted images (b,d). The left hemisphere harbors the gene-tagged 9L tumor, namely, CMV-LRP in (a) and (b) and PEG-LRP in (c) and (d), while the right hemisphere has a tumor derived from implantation of wild-type 9L cells. Note that PEG-LRP enables CEST imaging due to the activation of PEG-3 promoter by transcription factors present in the 9L tumor cells. Temporal changes in the ΔMTRasym values of each tumor type (e). The generalized estimating equation (GEE) approach demonstrated difference in CEST contrast at 3.4 ppm between tumors derived from wild-type (9L) and gene-tagged (9LPEG-LRP) cells (f). The scale in (b and d) is of MTRasym and in (e) the scale is of ΔMTRasym. Mean ± standard deviation; n = 8.