Simultaneous Tc-99m PYP/Tl-201 dual-isotope SPECT myocardial imaging in patients with suspected cardiac amyloidosis

Balaji Tamarappoo, Yuka Otaki, Osamu Manabe, Mark Hyun, Stephanie Cantu, Yoav Arnson, Heidi Gransar, Sean W. Hayes, John D. Friedman, Louise Thomson, Piotr Slomka, Damini Dey, Robert Vescio, Jignesh Patel, Daniel S. Berman*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

22 Scopus citations


Introduction: Assessment of myocardial uptake of Tc-99m-pyrophosphate (Tc-99m PYP) is pivotal in distinguishing transthyretin-associated cardiac amyloidosis (ATTR) from light chain amyloid (AL). It is often difficult to differentiate myocardial uptake from blood pool radioactivity with planar imaging or SPECT. We studied whether simultaneous dual-isotope Tc-99m PYP/Tl-201 SPECT improves assessment of Tc-99m PYP uptake compared to single-isotope SPECT. Methods: Simultaneous Tc-99m PYP/Tl-201 dual-isotope SPECT was acquired in 112 patients studied for possible cardiac amyloidosis. Visual interpretation was performed by two observers on single-isotope followed by dual-isotope SPECT. Heart-to-contralateral lung ratio (H/CL) of myocardial counts quantified by single-isotope and dual-isotope SPECT was compared between ATTR, AL, and no amyloidosis groups. Results: In 112 patients (39 ATTR and 26 AL patients, and 47 no amyloidosis), a lower proportion of no amyloidosis and AL patients were classified visually as equivocal with dual-isotope SPECT compared to single-isotope SPECT (2% vs 19%, P = 0.02 and 8% vs 35%, P = 0.04, respectively). H/CL measurements with single-isotope and dual-isotope were lower in AL and no amyloidosis patients vs ATTR patients (P < 0.05). Interobserver agreement of visual assessment was improved with dual-isotope SPECT (P = 0.03). AUCs for detection of ATTR by visual assessment and H/CL quantification were higher with dual-isotope (0.94 and 0.95, respectively) compared to single-isotope SPECT (0.84, P = 0.001 and 0.92, P = 0.02). Conclusion: Tc-99m PYP/Tl-201 SPECT improves visual differentiation of ATTR and AL amyloidosis compared to single-isotope SPECT. Visual assessment and H/CL quantitation with dual-isotope SPECT provide similar discrimination between patients with ATTR and AL amyloidosis.

Original languageEnglish
Pages (from-to)28-37
Number of pages10
JournalJournal of Nuclear Cardiology
Issue number1
StatePublished - 1 Feb 2020
Externally publishedYes


FundersFunder number
National Heart, Lung, and Blood InstituteR56HL131871
Dr. Miriam and Sheldon G. Adelson Medical Research Foundation
Cedars-Sinai Medical Center


    • ATTR
    • Cardiac amyloidosis
    • SPECT
    • Tc-99m-pyrophosphate
    • Tl-201
    • transthyretin


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