Non-invasive detection and differentiation of cardiac amyloidosis using 99mTc-pyrophosphate scintigraphy and 11C-Pittsburgh compound B PET imaging

Abstract

Purpose To investigate the utility of the combined use of 11C-Pittsburgh compound B (11C-PiB) positron emission tomography (PET) imaging and 99mTc-pyrophosphate (99mTc-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 11C-PiB PET and 99mTc-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 11C-PiB and 99mTc-PYP were analyzed in each patient. Results Cardiac amyloidosis was detectable by 99mTc-PYP scintigraphy or 11C-PiB PET in all systemic amyloidosis patients with cardiac involvement. 99mTc-PYP scintigraphy and 11C-PiB PET showed an interesting complementary relation. Strict combination of positive 11C-PiB and negative 99mTc-PYP uptake (PiB pattern) was observed in all AL amyloidosis patients with cardiac involvement. In contrast, strict combination of positive 99mTc-PYP and negative 11C-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 TTR gene testing.