Research Article
Impact of Global Mean Normalization on Regional Glucose Metabolism in the Human Brain
Table 4
Thesholding -maps in Figures 3–6 revealed unidirectional and bidirectional changes, which is illustrated in terms of the number of positive (P) and negative (N) clusters, where they, respectively, correspond to areas of higher and lower intensities compared to control. See Table 1 for abbreviations of conditions. The positive clusters in the thresholded GMN (PGMN) versus qCMRglc (PqCMR) -maps were 8 times greater, whereas negative clusters in the thresholded GMN (NGMN) versus qCMRglc (NqCMR) -maps were 2 times greater. Similarity between thresholded GMN and qCMRglc-maps was assessed by several metrics: (i) the total number of clusters given by the sum of P and N clusters, for qCMRglc () and GMN () thresholded -maps; (ii) the difference between the P clusters () for GMN and qCMRglc thresholded -maps (); (iii) the difference between the clusters (DN) for GMN and qCMRglc thresholded -maps (). Analysis shows that TGMN was about 4 times greater than TqCMR, whereas both DP and DN were greater than 0, signifying that GMN thresholded -maps consistently revealed more bidirectional changes. For thresholded -maps, see Figure S3 for EMCS, MCS, and UWS versus control (HAEC); Figure S4 for Sev0.25, Sev0.5, and Des1 versus control (HAEC); Figure S5 for HAEO versus control (HAEC); and Figure S6 for CB versus control (HAEC).
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