Can 99mTc-Pyrophosphate Aid in Early Detection of Cardiac Involvement in Asymptomatic Variant TTR Amyloidosis?

Transthyretin Cardiac Amyloidosis in Older Adults: Optimizing Cardiac Imaging to the Corresponding Diagnostic and Management Goal

“…In elderly cohorts, both Tc99m-DPD and Tc99m-PYP detected ATTR-CA before any evidence of cardiac involvement on TTE [45, 47, 48, 64]. 99mTc-DPD cardiac uptake was found in 12 patients with ATTR (4 ATTRwt, 8 ATTRm) who had no echocardiographic evidence of cardiac involvement by wall thickness [45].…”

“…99mTc-DPD cardiac uptake was found in 12 patients with ATTR (4 ATTRwt, 8 ATTRm) who had no echocardiographic evidence of cardiac involvement by wall thickness [45]. In another study, among 12 patients with ATTRm and no evidence of infiltrative cardiomyopathy by normal TTE and biomarkers (N-terminal pro b-type natiuretic peptide [NT-proBNP], troponin-I), 10/12 had some abnormal Tc99m-PYP uptake and 7/12 had diagnostic levels of tracer uptake (grade 2 or 3) [64]. Although myocardial radiotracer uptake in these asymptomatic patients was lower than that seen in patients with ATTRm-related heart failure, it was significantly higher than in patients with non-ATTRm-related HFpEF, suggesting a role for Tc99m-PYP nuclear scintigraphy for early detection of ATTR-CA.…”

Role of Imaging in Evaluating Infiltrative Heart Disease

“…A similar tracer, Tc-99 m-3,3-diphosphono-1,2-propanodicarboxylic acid (DPD) is widely used in Europe [48]. Asymptomatic carriers of TTR mutations also exhibit avidity to Tc-99 m PYP, entertaining the possibility that it can be used as a screening test for early diagnosis prior to onset of heart failure symptoms [49]. It may also be possible to risk stratify patients with quantitative estimates from Tc-99 m PYP or DPD scanning.…”

Technetium 99m pyrophosphate radioisotope for diagnosis and prognosis of transthyretin cardiac amyloidosis: A call for collaboration

“…Other centers have compared a 1-vs 3-hour incubation time and demonstrated that the standardized methodology of 1-hour incubation time and only 10 mCi of Tc99m PYP are sufficient for highquality imaging, 3,8 even in patients with early-stage disease. 9 The 3-hour incubation time for Tc99 m PYP was derived from original literature of Tc99m PYP for imaging myocardial infarction 10,11 and from the Tc99m DPD protocol used in Europe, 12 which calculates a heart-to-whole body ratio. Three hours may not necessarily be the optimal incubation time for the Tc99m PYP H/CL ratio, which only requires planar imaging of the chest (not the whole body).…”