TTR and axial length measurement: Although amyloid PET tracers are not specifically connected to cardiac fibrils, they appear to have a greater affinity for AL than for ATTR amyloidosis, as evidenced by an autoradiographic study [13] which showed that the specific uptake of 18F-florbetapir was significantly increased in AL-CA samples compared to TTR-CA (2.48 ± 0.40 vs. 1.52 ± 0.22 DPM/mm2; p < 0.001; n = 10, respectively), indicating the different binding mechanisms and distinct biologic properties of CA disease entities (Figure 1).