Figure 1.
Average time-activity curves for [18F]FDG (a) and [18F]FECT (b), expressing uptake in the cerebral cortex (○), caudate-putamen (□) and cerebellum (Δ).
For [18F]FECT, specific-to-non-specific ratio (caudate-putamen to cerebellum (◊)) is also shown.
Figure 2.
Schematic representation of the functional PET atlases construction pathway.
The full arrows express the followed procedure, the arrows in dotted line the objective. On the standardized atlases a stereotactic grid is shown (2 mm interlines).
Figure 3.
Spatial correspondence achieved between the anatomical landmarks defined in the MRM image and the corresponding co-ordinates in Paxinos space.
Points marked with open symbols signify the MRM space, whereas points denoted with full symbols belong to the Paxinos space.
Figure 4.
[18F]FDG and [18F]FECT probabilistic atlases.
(a) Series of axial sections (ventral to dorsal, slice interval 1.2 mm, radiological orientated) through the mouse brain MRM atlas (top row) and co-registered [18F]FDG (middle row) and [18F]FECT (bottom row) small-animal PET template. (b) One representative coronal (radiological orientation) and sagittal slice through caudate-putamen. (c) Horizontal section through variance map at level z = −2.8 (relative to bregma). The mouse brain MRM atlas shows the pre-defined VOI map over-layed. Color bars indicate relative intensities for [18F]FDG; binding potential for [18F]FECT.
Table 1.
Mean [18F]FDG and [18F]FECT uptake, intersubject variability, test-retest and right-to-left asymmetry indices obtained using pre-defined VOI-analysis.
Figure 5.
(a) Representative fit of the cortical [18F]FDG time-activity-curve using a 3-compartment model (dashed line) and liver input function (solid line).
(b) Comparison of regional values of cMRglc derived from a 3-compartment model fit to SUVglc measured between 45 min and 60 min post injection. Solid line linear regression; spearman r = 0.73; p<0.0001.
Table 2.
Regional K*FDG, K1/k2, k3 and k4 estimates of [18F]FDG obtained from the mice scanned over 90 min using a 3-compartment model and liver input function.
Figure 6.
Statistical parametric maps of 6-OHDA mice.
Differences for the brain-regions have been color-coded and are superimposed on the MRM template. Series of axial sections with t-maps rendered on the MRM atlas of the mouse brain show significant reductions in glucose metabolism (a) and DAT availability (b). The colored bars on the right express T-score levels. The intersection points of the axial planes have been set to the position of the right caudate-putamen, i.e. (x,y) = (−1.8, 0.2) and (x,y) = (−2.0, 0.0) for [18F]FDG and [18F]FECT, respectively. Images are in radiological convention.
Table 3.
Estimates of registration accuracy for a simulated [18F]FDG and [18F]FECT image of a control and a 6-OHDA-lesioned animal, derived from the VOI map, after re-registration of randomly misaligned data.