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Clerc OF, Cuddy SAM, Robertson M, Vijayakumar S, Neri JC, Chemburkar V, Kijewski MF, Di Carli MF, Bianchi G, Falk RH, Dorbala S. Cardiac Amyloid Quantification Using 124I-Evuzamitide ( 124I-P5+14) Versus 18F-Florbetapir: A Pilot PET/CT Study. JACC Cardiovasc Imaging 2023; 16:1419-1432. [PMID: 37676210 PMCID: PMC10758980 DOI: 10.1016/j.jcmg.2023.07.007] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/23/2023] [Revised: 07/20/2023] [Accepted: 07/20/2023] [Indexed: 09/08/2023]
Abstract
BACKGROUND Cardiac amyloid quantification could advance early diagnosis of amyloid cardiomyopathy (CMP) and treatment monitoring. However, current imaging tools are based on indirect measurements. 124I-evuzamitide is a novel pan-amyloid radiotracer binding to amyloid deposits from multiple amyloidogenic proteins. Its ability to quantify cardiac amyloid has not yet been investigated. OBJECTIVES The objectives of this pilot study were to quantify myocardial 124I-evuzamitide uptake and to compare its diagnostic value to 18F-florbetapir in participants with amyloid CMP and control subjects. METHODS This study included 46 participants: 12 with light-chain (AL) CMP, 12 with wild-type transthyretin (ATTRwt) CMP, 2 with hereditary amyloidosis, and 20 control subjects. All amyloidosis participants underwent positron emission tomography/computed tomography with 124I-evuzamitide and 18F-florbetapir. Control subjects underwent 124I-evuzamitide (n = 10) or 18F-florbetapir (n = 8) positron emission tomography/computed tomography. Left ventricular percent injected dose (LV% ID) was measured as mean activity concentration × myocardial volume/injected activity. High LV %ID was defined using Youden's index. RESULTS In CMP participants, median age was 74 years and 92% were men. 124I-evuzamitide LV %ID differed across groups: median AL-CMP 1.48 (IQR: 1.12-1.89), ATTRwt-CMP 2.12 (IQR: 1.66-2.47), and control subjects 0.00 (IQR: 0.00-0.01; overall P < 0.001). High LV %ID perfectly discriminated CMP from control subjects. Discrimination performance was similar for 18F-florbetapir LV %ID. Notably, for ATTRwt-CMP, LV %ID was higher with 124I-evuzamitide than 18F-florbetapir (P = 0.002). 124I-evuzamitide LV %ID was correlated with interventricular septum thickness (Spearman's ρ = 0.78) and LV global longitudinal strain (ρ = 0.54) from echocardiography, and with LV mass index (ρ = 0.82) and extracellular volume (ρ = 0.51) from cardiac magnetic resonance. CONCLUSIONS 124I-evuzamitide demonstrates uptake by cardiac amyloid and accurately discriminates amyloid CMP from control subjects. In AL-CMP, discrimination performance is similar to 18F-florbetapir. In ATTRwt-CMP, performance may be better with 124I-evuzamitide. Moderate-to-strong correlations of 124I-evuzamitide uptake with cardiac structural and functional metrics suggest valid amyloid quantification. Hence, 124I-evuzamitide is a promising novel radiotracer to detect and quantify cardiac amyloid.
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Affiliation(s)
- Olivier F Clerc
- Division of Nuclear Medicine and Molecular Imaging, Department of Radiology, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts, USA; Cardiac Amyloidosis Program, Cardiovascular Division, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts, USA
| | - Sarah A M Cuddy
- Cardiac Amyloidosis Program, Cardiovascular Division, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts, USA; CV imaging program, Cardiovascular Division and Department of Radiology, Brigham and Women's Hospital, Boston, Massachusetts, USA
| | - Matthew Robertson
- CV imaging program, Cardiovascular Division and Department of Radiology, Brigham and Women's Hospital, Boston, Massachusetts, USA
| | - Shilpa Vijayakumar
- Cardiac Amyloidosis Program, Cardiovascular Division, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts, USA; CV imaging program, Cardiovascular Division and Department of Radiology, Brigham and Women's Hospital, Boston, Massachusetts, USA
| | - Jocelyn Canseco Neri
- Division of Nuclear Medicine and Molecular Imaging, Department of Radiology, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts, USA; Cardiac Amyloidosis Program, Cardiovascular Division, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts, USA
| | - Vaidehi Chemburkar
- Division of Nuclear Medicine and Molecular Imaging, Department of Radiology, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts, USA; Cardiac Amyloidosis Program, Cardiovascular Division, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts, USA
| | - Marie Foley Kijewski
- Division of Nuclear Medicine and Molecular Imaging, Department of Radiology, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts, USA
| | - Marcelo F Di Carli
- Division of Nuclear Medicine and Molecular Imaging, Department of Radiology, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts, USA; CV imaging program, Cardiovascular Division and Department of Radiology, Brigham and Women's Hospital, Boston, Massachusetts, USA
| | - Giada Bianchi
- Cardiac Amyloidosis Program, Cardiovascular Division, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts, USA; Division of Hematology, Department of Medicine, Brigham and Women's Hospital Boston, Massachusetts, USA
| | - Rodney H Falk
- Cardiac Amyloidosis Program, Cardiovascular Division, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts, USA
| | - Sharmila Dorbala
- Division of Nuclear Medicine and Molecular Imaging, Department of Radiology, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts, USA; Cardiac Amyloidosis Program, Cardiovascular Division, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts, USA; CV imaging program, Cardiovascular Division and Department of Radiology, Brigham and Women's Hospital, Boston, Massachusetts, USA.
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