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Abstract 12769: Improving Performance of Technetium-99m Pyrophosphate Imaging for Transthyretin Cardiac Amyloidosis
Abstract   Peer reviewed

Abstract 12769: Improving Performance of Technetium-99m Pyrophosphate Imaging for Transthyretin Cardiac Amyloidosis

Daniel Davies, John Wells Askew, Joanne Benson, Panithaya Chareonthaitawee, Geoffrey Johnson, Robert Glynn, Eli Muchtar, Angela Dispenzieri, Morie Gertz, Martha Grogan, …
Circulation (New York, N.Y.), v 140(Suppl_1 Suppl 1), A12769
19 Nov 2019
DOI: https://doi.org/10.1161/circ.140.suppl_1.12769

Abstract

IntroductionTechnetium-99m pyrophosphate (Tc PYP) scintigraphy is considered reliable for the non-invasive diagnosis of transthyretin cardiac amyloidosis (TTR-CA). Conventional planar uptake ratios (H/CL) may be confounded by blood pool/extra-cardiac isotope uptake reducing the diagnostic accuracy of planar imaging.HypothesisSingle-photon emission computed tomography-computed tomography (SPECT-CT) acquisition improves the performance of Tc PYP scintigraphy for TTR-CA.MethodsWe performed a retrospective analysis of all patients undergoing simultaneous Tc PYP planar and SPECT-CT scintigraphy for suspected TTR-CA at Mayo Clinic from 2014 to 2018 (n=749). At 3 hours, a planar H/CL value > 1.3 was considered positive (POS) and ≤ 1.3 was negative (NEG). SPECT-CT images were assessed for myocardial uptake by visual inspection and coded POS or NEG. Clinical data were categorized by planar/SPECT-CT concordance. Planar POS but SPECT-CT NEG patients were compared to planar POS and SPECT-CT POS patients.ResultsSee Table. A total of 381 patients were NEG by both planar and SPECT-CT, while 351 patients were POS by planar imaging. Of these planar POS patients, 46 (13.1%) were SPECT-CT NEG and 305 were SPECT-CT POS. Compared to patients POS by both modalities, planar POS SPECT-CT NEG patients had lower H/CL values, were more commonly female, and had received higher Tc PYP doses. Further, they had lower NTproBNP and Troponin T levels, and less severe perturbations in cardiac structure and function on echocardiography. Additionally, 17 patients were POS by SPECT-CT but not by planar imaging (data not shown), of which, 3 patients had an endomyocardial biopsy all of which were positive for ATTR on tissue mass spectrometry.ConclusionsPatients with POS planar but NEG SPECT-CT Tc PYP have a distinct phenotype which suggests the absence of TTR-CA. These data support combined use of planar and SPECT-CT-based methods for diagnosis of TTR-CA.

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