Article Figures & Data
Figures
- FIGURE 1.
Manual definition of reference region. Sum images of AD patient are generated using early (A) and late (B) summation of dynamic 11C-PIB PET images, which are used to delineate ROI representing reference region (C).
- FIGURE 2.
Optimized manual method for definition of reference region. Sum images of AD patient in Figure 1 are generated using early (A) and late (B) summation of dynamic 11C-PIB PET images. Next, 40% cutoff is performed (C), and new ROI defining cerebellum is drawn manually (D).
- FIGURE 3.
MVW-PCA application on dynamic 11C-PIB PET images of AD patient. Images from components 1–3 are shown in different views. MVW-PC1 (A–C) corresponds to kinetics of tracer in regions affected by Aβ-amyloid deposits as frontal cortex, anterior cingulate cortex, and temporal cortex. In MVW-PC2 (D–F), delineated cortical areas are devoid of amyloid. Projection planes were selected to illustrate cerebellum. In MVW-PC3 (G–I), kinetic behavior of tracer in blood was extracted and major blood vessels are seen.
- FIGURE 4.
MVW-PCA application on dynamic 11C-PIB PET images of HC. Images from components 1–3 are shown in different views. MVW-PC1 (A–C) corresponds to kinetics of tracer in regions with 11C-PIB retention as thalamus. In MVW-PC2 (D–F), white matter is extracted and delineated. In MVW-PC3 (G–I), kinetic behavior of tracer in blood was extracted and major blood vessels are seen.
- FIGURE 5.
Illustration of automatic definition of ROI representing cerebellum, using MVW-PC2 image (A), binary image (B), selected area representing reference region (C), and edge pixels imported into MVW-PC3 image for further exploration (D).
- FIGURE 6.
Time–activity curves plotted using arbitrarily chosen reference region of AD patient (Fig. 5) generated by automatic method (red line) and manual method (blue line).
- FIGURE 7.
Illustration of automatic definition of ROI representing cerebellum using MVW-PC2 image (A and C); defined ROI was imported into corresponding slice in MVW-PC3 image (B and D) for 2 arbitrarily chosen AD patients.
- FIGURE 8.
MVW-PC2 image (A) obtained by applying MVW-PCA on arbitrarily chosen HC (also shown in Fig. 4). Corresponding inverted MVW-PC2 image (B) was generated by inverted weighting factors obtained from application of MVW-PCA. Outlined reference region in MVW-PC2 image was obtained using automatic method (C), and ROI was imported into MVW-PC3 image for further exploration (D).
- FIGURE 9.
Both automatically (yellow) and manually (red) delineated reference regions were imported into corresponding PC3 image. Here, ROI that was defined manually (red) covered parts of blood vessels in both right and left sides of reference region. Mean value of pixels covered by ROI was affected. Automatically defined ROI (yellow) did not cover blood vessels.
- FIGURE 10.
MRI scan of AD patient (A), fused image using same MRI slice corresponding MVW-PC2 image (B), and MRI scan with delineated ROI (representing reference region) superimposed (C) are shown.
- FIGURE 11.
Diagram showing mean activity concentration, with statistical variation of pixel values within ROIs positioned in test and retest PET studies on AD patient, when reference region is repeatedly defined using manual method. Pat. = patient.
- FIGURE 12.
Diagram comparing correlation variation (coefficient of variance) of mean pixel values of ROIs positioned in test and retest PET studies on AD patient, when reference region is defined manually and repeatedly. Pat. = patient.
Tables
Patient no. Mean activity Absolute value of activity difference(%) No. of pixels Automatic Manual Automatic Manual 1 3,248.52 3,163.99 2.60 684 204 2 3,363.34 3,459.09 2.85 858 614 3 1,961.70 2,140.11 9.09 905 778 4 4,203.95 4,062.69 3.36 827 703 Difference in patient 3 is largest because manually defined ROI covered blood vessels (Fig. 9)
