Published in:
01-02-2018 | Original Article
Standardization of 99mTechnetium pyrophosphate imaging methodology to diagnose TTR cardiac amyloidosis
Authors:
Sabahat Bokhari, MD, Rachelle Morgenstern, MPH, Richard Weinberg, MD, PhD, Mona Kinkhabwala, MD, Demetrios Panagiotou, MD, Adam Castano, MD, Albert DeLuca, MD, Kontak Andrew, MD, Zhezhen Jin, PhD, Mathew S. Maurer, MD
Published in:
Journal of Nuclear Cardiology
|
Issue 1/2018
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Abstract
Background
Technetium pyrophosphate (99mTc-PYP) imaging to diagnose transthyretin cardiac amyloidosis (ATTR-CA) has been increasingly utilized. The objective of this study is to provide a standardized 99mTc-PYP imaging protocol to diagnose ATTR-CA.
Methods
104 scans from 45 subjects with biopsy-proven ATTR-CA or light-chain cardiac amyloidosis (AL) were assessed. Multiple scans were obtained using different counts (750 vs 2000 K), times to acquisition (1 vs 2 to 4 hours), processing matrix (256 vs 128), and
99mTc-PYP dose. Image quality and extracardiac activity was assessed. Quantitative methods using heart-to-contralateral ratios (H/CL) and a visual semiquantitative scale were used to diagnose ATTR-CA.
19 The correlation between H/CL ratios and reproducibility of semiquantitative visual scores, acquired using various imaging parameters, were evaluated.
Results
All imaging parameters had good to excellent image quality. 750 vs 2000 K counts, 1 hour acquisition and 256 matrix, had lower extracardiac activity (P = .00018). 10 mCi of 99mTc-PYP v. higher doses showed excellent image quality and less extracardiac activity (P = .0015). Correlation of H/CL ratios was strong (r ≥ 0.92) and reproducibility of semiquantitative visual scores was high (Kappa = 95%).
Conclusion
An imaging protocol using 750 K counts, 10 mCi of 99mTc-PYP, and a 256 matrix was chosen as the standardized imaging protocol since it provided the shortest overall study time (1 vs 2 to 4 hours) and lowest radiation exposure (3 vs 8 to 10 mSv).