Efficient 1-Hour Technetium-99 m Pyrophosphate Imaging Protocol for the Diagnosis of Transthyretin Cardiac Amyloidosis

Ahmad Masri, Syed Bukhari, Shahzad Ahmad, Ricardo Nieves, Yvonne S. Eisele, William Follansbee, Amy Brownell, Timothy C. Wong, Erik Schelbert, Prem Soman

Research output: Contribution to journalArticlepeer-review

50 Scopus citations


Background: Technetium-99 m pyrophosphate protocols for transthyretin cardiac amyloidosis diagnosis have variably used 1- and 3-hour imaging time points. We investigated whether imaging at 1 hour with superior efficiency had comparable diagnostic accuracy as 3-hour imaging. Methods: This is a registry analysis of patients with suspected transthyretin cardiac amyloidosis referred for technetium-99 m pyrophosphate at a single tertiary center from June 2015 through January 2019. Patients underwent planar and single-photon emission computed tomography (SPECT) imaging at 1 and 3 hours. A positive Tc-99m pyrophosphate study was defined by the presence of diffuse myocardial tracer uptake on SPECT. For planar imaging, visual semiquantitative (grades 0-3, ≥2 considered positive) and quantitative heart to contralateral ratios (≥1.5 considered positive) were used. Results: Two hundred thirty-three patients (69% men; median age, 77 [69-83] years) underwent the study protocol. There were 60 (25.8%) patients with diffuse myocardial uptake, 1 (0.4%) with regional uptake, and 172 (73.8%) with no myocardial uptake. Results of SPECT were identical at 1 and 3 hours. Planar imaging at 1 hour had 98% sensitivity and 96% specificity. Planar grade 0 uptake or heart to contralateral ratio ≤1.2 and planar grade 3 uptake or heart to contralateral ratio ≥2.0 were always associated with negative and positive SPECT, respectively. For planar grades 1 and 2 uptake and heart to contralateral ratio 1.3 to 1.9, SPECT was needed to make a diagnosis. No patient with light-chain cardiac amyloidosis had positive SPECT. Conclusions: An efficient 1-hour technetium-99 m pyrophosphate protocol had comparable diagnostic performance to a 3-hour protocol.

Original languageEnglish (US)
Pages (from-to)E010249
JournalCirculation: Cardiovascular Imaging
Issue number2
StatePublished - Feb 1 2020
Externally publishedYes


  • heart
  • humans
  • prealbumin
  • records
  • registries

ASJC Scopus subject areas

  • Radiology Nuclear Medicine and imaging
  • Cardiology and Cardiovascular Medicine


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