Non-invasive detection and differentiation of cardiac amyloidosis using Tc-pyrophosphate scintigraphy and C-Pittsburgh compound B PET imaging.

PURPOSE

To investigate the utility of the combined use of C-Pittsburgh compound B (C-PiB) positron emission tomography (PET) imaging and Tc-pyrophosphate (Tc-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 C-PiB PET and 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 C-PiB and Tc-PYP were analyzed in each patient.

RESULTS

Cardiac amyloidosis was detectable by Tc-PYP scintigraphy or C-PiB PET in all systemic amyloidosis patients with cardiac involvement. Tc-PYP scintigraphy and C-PiB PET showed an interesting complementary relation. Strict combination of positive C-PiB and negative Tc-PYP uptake (PiB pattern) was observed in all AL amyloidosis patients with cardiac involvement. In contrast, strict combination of positive Tc-PYP and negative 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 and gene testing.