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FIGURE 3. PET attenuation maps and corresponding attenuation-corrected PET images of NCAT phantom (A–D) and typical patient scan (E–H), based on the following attenuation data: unenhanced data (reference data; mean CT attenuation in left ventricle in E, 40 HU) (A and E); nonprocessed contrast-enhanced data (mean CT attenuation in left ventricle in F, 370 HU) (B and F); contrast-enhanced data with cylinder-threshold contrast agent correction (C and G); and contrast-enhanced data with global-threshold contrast agent correction (D and H). Shown on right are differences between PET images based on CE attenuation data and PET images based on unenhanced CE data. PET images using nonprocessed enhanced CT scan information overestimate uptake in left ventricular wall. Arrow in E refers to line profile of Figure 4. CE = contrast-enhanced; CTC = cylinder-threshold correction; GTC = global threshold correction.
