Non-invasive detection and differentiation of cardiac amyloidosis using99mTc-pyrophosphate scintigraphy and11C-Pittsburgh compound B PET imaging

Purpose To investigate the utility of the combined use of(11)C-Pittsburgh compound B (C-11-PiB) positron emission tomography (PET) imaging and(99m)Tc-pyrophosphate (Tc-99m-PYP) scintigraphy for detection and differentiation of three major types of cardiac amyloidosis, i.e. immunoglobulin light chain (AL), hereditary transthyretin (ATTRv), and wild-type transthyretin (ATTRwt) amyloidosis. Methods Whole-body(11)C-PiB PET and(99m)Tc-PYP scintigraphy were performed in 17 patients with AL amyloidosis, 22 patients with ATTRv, and eight patients with ATTRwt amyloidosis. The correlations between organ involvement and the uptake of(11)C-PiB and(99m)Tc-PYP were analyzed in each patient. Results Cardiac amyloidosis was detectable by(99m)Tc-PYP scintigraphy or(11)C-PiB PET in all systemic amyloidosis patients with cardiac involvement.Tc-99m-PYP scintigraphy and(11)C-PiB PET showed an interesting complementary relation. Strict combination of positive(11)C-PiB and negative(99m)Tc-PYP uptake (PiB pattern) was observed in all AL amyloidosis patients with cardiac involvement. In contrast, strict combination of positive(99m)Tc-PYP and negative(11)C-PiB uptake (PYP pattern) was observed in all ATTRwt amyloidosis patients with cardiac involvement. ATTRv amyloidosis patients with cardiac involvement were divided into two groups: PiB pattern or PYP pattern. All of the early-onset V30M (p.V50M) ATTRv patients showed the PiB pattern, whereas all of the late-onset V30M and non-V30M ATTRv patients showed the PYP pattern. Conclusions All three major types of cardiac amyloidosis can be detected and differentiated non-invasively by combined use of the two amyloid imaging methods andTTRgene testing.