TTR and aortic stenosis: Increased septal 18F-fluoride activity was observed in patients with ATTR amyloid (1.13 ± 0.16) compared to healthy volunteers (0.86 ± 0.10, P = .0002) and patients with both AL amyloid (0.95 ± 0.08, P = .01) and aortic stenosis (0.73 ± 0.12, P < .0001; Table 3, Figure 3A).