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Heart failure & cardiomyopathiesResearch article

Kinetics of Technetium-Labeled Cardiac Amyloid Radionuclide Imaging

Circ Cardiovasc ImagingPublished

  • serial single-photon emission computed tomography with computed tomography imaging
  • quantitative
  • cadmium zinc telluride system (SpectrumDynamics Veriton)
  • mixed-effects models with splines
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Authors' conclusion

Both pyrophosphate and HMDP provide diagnostic myocardial visualization within 10 minutes of injection, with similar myocardial SUVs that decline linearly over time. HMDP demonstrates more rapid blood pool clearance and greater bone uptake, resulting in earlier skeletal dominance and often requiring upward adjustment of image intensity to visualize myocardial uptake on delayed images. The results provide kinetic data that can inform future protocol optimization and quantitative standardization.

Study context

Population
Subjects undergoing evaluation for transthyretin cardiac amyloidosissubjects imaged, 16 with positive imaging · pyrophosphate 11 · hydroxymethylene diphosphonate (HMDP) 13
Participants
Twenty-four subjects
Comparison
Mixed-effects models with splines compared time-activity trends between tracers
  • pyrophosphaten = 11
  • HMDPn = 13

Main finding

As reported in the abstract

Visual myocardial uptake above the blood pool · within 10 minutes post-injection

All 16 subjects with positive imaging demonstrated visual myocardial uptake above the blood pool

16

Further findings

Time at which bone activity exceeded myocardial activity · earlier with HMDP

P < 0.001

  • Time at which bone activity exceeded myocardial activity: visual reduction of myocardial intensity with HMDP due to scaling

Myocardial, blood pool and bone standardized uptake values (SUVs) · 5 minutes to 3 hours post-injection

Myocardial SUVs were similar between tracers and decreased linearly over time
Blood pool SUVs declined biexponentially
Bone SUVs increased exponentially

Blood pool clearance, bone uptake and heart-to-blood pool target-to-background ratios · across all time points

HMDP exhibited faster blood pool clearance and higher bone uptake than pyrophosphate, resulting in higher heart-to-blood pool target-to-background ratios

Association between quantitative indices and clinical disease severity markers

No association was observed

Original publication

Kinetics of Technetium-Labeled Cardiac Amyloid Radionuclide Imaging. Circ Cardiovasc Imaging. Published 10 April 2026. doi:10.1161/circimaging.125.019371
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Summarised from the published abstract; every number is checked against it