99mTc-DPD scintigraphy in immunoglobulin light chain (AL) cardiac amyloidosis

Abstract

Aims Technetium-99m-labelled 3,3-diphosphono-1,2-propanodicarboxylic acid (99mTc-DPD scintigraphy) is recognized as highly accurate for the non-invasive diagnosis of transthyretin (ATTR) cardiac amyloidosis (CA). A proportion of patients with immunoglobulin light chain (AL) CA have also been reported to show cardiac 99mTc-DPD uptake. Herein, we assessed the frequency and degree of cardiac 99mTc-DPD uptake and its clinical significance among patients with AL CA. Methods and results Between 2010 and 2017, 292 consecutive patients with AL CA underwent 99mTc-DPD scintigraphy and were included in this study: 114 (39%) had cardiac 99mTc-DPD uptake: grade 1 in 75%, grade 2 in 17%, and grade 3 in 8% of cases. Patients with cardiac 99mTc-DPD uptake had poorer cardiac systolic function and higher N-terminal pro-brain natriuretic peptide. No differences were noted in cardiac magnetic resonance parameters between patients with and without cardiac 99mTc-DPD uptake (N = 19 and 42, respectively). Patients with cardiac 99mTc-DPD uptake showed a trend to worse survival than those with no uptake (log-rank P = 0.056). Among 22 patients who underwent serial 99mTc-DPD scintigraphy, 5 (23%) showed reduction in the grade of cardiac uptake. Conclusions In this large cohort of patients with AL CA, 99mTc-DPD scintigraphy ∼40% of cases showed cardiac uptake, including grade 2–3 in 10% of all patients (25% of those with cardiac 99mTc-DPD uptake). Cardiac 99mTc-DPD uptake was associated with poorer cardiac function and outcomes. These data highlight the critical importance of ruling out AL amyloidosis in all patients with cardiac 99mTc-DPD uptake to ensure such patients are not assumed to have ATTR CA.

99mTechnetium‐pyrophosphate scintigraphy: a practical guide for early diagnosis of transthyretin amyloid cardiomyopathy

“…False‐positive cases in 99m Tc‐PYP scintigraphy for ATTR‐CM may include Grade 2 or 3 myocardial uptake; a recent history of acute myocardial infarction 54 ; AL amyloidosis 34 , 54 , 69 , 70 , 71 , 72 , 73 ; apolipoprotein AI amyloidosis (AApoAI), apolipoprotein AII amyloidosis (AApoAII), apolipoprotein A‐IV amyloidosis (ApoAAIV), or β2‐microglobulin amyloidosis (Aβ2M) 10 ; hypertrophic cardiomyopathy 74 , 75 ; hydroxychloroquine toxicity 76 ; and cardiac blood pools. 54 Case reports on false‐positive myocardial uptake following intravenous iron injections have been published for 99m Tc‐DPD and 99m Tc‐HMDP scintigraphy.…”

Fat biopsy from a pocket of cardiac implantable electronic device: An alternative diagnostic option for cardiac amyloidosis

“…Radionuclide bone scintigraphy with technetium-labeled bisphosphonates has been widely recognized as a useful test for diagnosing TTR-CA 6 ; however, false-positives in amyloid light-chain amyloidosis, hypertrophic cardiomyopathy, and false-negatives have recently been reported in multiple reports. 7 , 8 , 9 , 10 , 11 Therefore, histological confirmation of the diagnosis of amyloidosis remains essential in some cases.…”

Nuclear Molecular Imaging of Disease Burden and Response to Treatment for Cardiac Amyloidosis

“…Previous studies report that the H/CL ratio of ≥1.5 on 1 h images or H/CL ratio ≥ 1.3 on late (3 h) images of 99m Tc-PYP scintigraphy can clearly distinguish TTR from AL amyloidosis with over 90% sensitivity and specificity [ 21 , 27 ]. Of note, Perugini grade 1 can be found in as many as 9% of patients with TTR-CA [ 7 ], and up to 25% of patients with AL-CA will have grade 2 or 3 radiotracer uptake [ 28 ]. Thus, AL amyloidosis should be excluded when ordering a bone scintigraphy scan for diagnosing TTR-CA.…”