Article Figures & Data
Figures
- FIGURE 1.
11C-DTBZ K1 and 18F-FDG images at 3 brain levels for one representative subject from each group. All images are normalized to cerebellar vermis.
- FIGURE 2.
Group average deficits of 11C-DTBZ K1 (solid bars) and 18F-FDG (hatched bars) relative to NC for 22 cortical regions. Shown are mean and SD for FTD (A; n = 7), AD (B; n = 25), and DLB (C; n = 20) expressed as a percentage of NC (n = 19) mean. All values are normalized to cerebellar vermis.
- FIGURE 3.
Correlations between 18F-FDG and 11C-DTBZ K1 across 22 cortical regions for selected individuals from each diagnostic group. Both 18F-FDG and K1 values are normalized to cerebellar vermis. The subject selected from each group was the individual having a correlation coefficient closest to the group average (Table 1, column 2). Correlation coefficients are 0.953, 0.945, 0.919, and 0.887 for the selected FTD (A), AD (B), DLB (C), and NC (D) subjects, respectively.
- FIGURE 4.
Discrepancies between clinical and PET diagnoses. Shown are 11C-DTBZ K1, 18F-FDG, and 11C-DTBZ DV images at 3 brain levels for 2 subjects whose clinical diagnosis at time of PET was different than classifications by both logistic regression and all physician ratings. Clinical diagnosis at time of scan is given first, followed by PET classification in brackets.
Tables
Group n 18F-FDG vs. 11C-DTBZ K1 18F-FDG vs. 11C-DTBZ DV 11C-DTBZ K1 vs. 11C-DTBZ DV FTD 7 0.947 ± 0.024 0.08 ± 0.22 0.20 ± 0.24 AD 25 0.944 ± 0.038 0.28 ± 0.30 0.34 ± 0.29 DLB 20 0.922 ± 0.037 0.49 ± 0.22 0.51 ± 0.22 NC 19 0.893 ± 0.042 0.23 ± 0.28 0.34 ± 0.26 All 71 0.924 ± 0.043 0.31 ± 0.27 0.37 ± 0.26 Values are mean ± SD of Pearson correlation coefficients (r) for each group.
Correlation Correlation parameter Mean ± SD Same-parameter 18F-FDG vs. 18F-FDG 0.61 ± 0.22 Same-parameter 11C-DTBZ K1 vs. 11C-DTBZ K1 0.59 ± 0.23 Between-parameters 18F-FDG vs. 11C-DTBZ K1 0.58 ± 0.22 Same-parameter 11C-DTBZ DV vs. 11C-DTBZ DV 0.29 ± 0.41 Between-parameters 11C-DTBZ DV vs. 18F-FDG 0.03 ± 0.32 Between-parameters 11C-DTBZ DV vs. 11C-DTBZ K1 0.06 ± 0.32 Values are mean ± SD of Pearson correlation coefficients (r) for all possible between-subject combinations (71!/[69! × 2!] for same-parameter correlations; 71!/69! for between-parameter correlations).
Classification PET parameter Discriminating variable* Odds ratio† P value‡ Sensitivity§ (%) Specificity§ (%) FTD/AD/DLB vs. NC K1 BA40 K1 0.81 <0.0001 90.4 84.2 18F-FDG BA40 18F-FDG 0.72 0.0005 92.3 78.9 K1+DV‖ BA40 K1 0.81 0.0002 88.5 84.2 DV 0.99 0.396 18F-FDG+DV BA40 18F-FDG 0.72 0.0012 90.4 78.9 DV 1.00 0.881 AD/DLB vs. FTD K1 BA24–BA31 K1 1.13 0.0116 73.3 57.1 18F-FDG BA24–BA31 18F-FDG 1.14 0.0087 77.8 71.4 K1+DV BA24–BA31 K1 1.14 0.0320 73.3 57.1 DV 0.99 0.286 18F-FDG+DV BA24–BA31 18F-FDG 1.12 0.0282 68.9 57.1 DV 0.99 0.345 DLB vs. AD K1 BA24–BA17 K1 1.12 0.0007 70.0 76.0 18F-FDG BA24–BA17 18F-FDG 1.28 0.0020 85.0 84.0 K1+DV BA24–BA17 K1 1.15 0.311 90.0 96.0 DV 0.84 0.178 18F-FDG+DV BA24–BA17 18F-FDG 1.04 0.737 90.0 96.0 DV 0.83 0.159 ↵* BA(s) that provided best discrimination for each given test.
↵† An increase of 0.01 in the discriminating variable multiplies the odds of being in the first of the 2 comparison groups by this factor. A value of 1.0 corresponds to lack of discrimination. The magnitude of deviation from 1.0 is a measure of the ability of variable to discriminate the 2 groups.
↵‡ P value for a test of null hypothesis that odds ratio of the discriminating variable is 1.0.
↵§ Sensitivity and specificity are based on cross-validation—that is, when each case is classified, logistic regression is recomputed with that case excluded.
↵‖ DV is bilateral average of 11C-DTBZ VMAT2 binding measures in putamen.
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