**Author Listing - Lead/ Submitting Author (we will be communicating with this individual): Name, Institution, City and State where the work was done. Co-authors will be added in a separate section.**
Morris Kim, MD
Knight Cardiovascular Institute, Oregon Health & Science University (OHSU)
Portland, OR

**Main Body of the Abstract**
Introduction: Cardiac magnetic resonance imaging (CMR) allows for the assessment of cardiac structure, function, and surrogates of amyloid load such as extracellular volume fraction (ECV). 124I-evuzamitide (AT-01) is a novel pan-amyloid PET radiotracer. We investigated the relationship between 124I-evuzamitide myocardial uptake, ECV, and other measures of cardiac structure and function.
Methods: Cardiac amyloidosis was diagnosed by standard clinical, laboratory, biopsy, and imaging criteria. All subjects underwent hybrid cardiac PET/MRI with 124I-evuzamitide (mean dose 1.05±0.02 mCi). Traditional measures of cardiac structure and function were assessed on CMR. 124I-evuzamitide uptake was quantified using LV SUVR (ratio of LV myocardium SUV/LV blood pool SUV).
Results: We enrolled 50 patients (28 ATTR, 12 AL and 10 without systemic amyloidosis, mean age 72±9.1, 74% male, 82% ≥ NYHA class II). Median 124I-evuzamitide LV SUVR was 1.7 (1.1, 1.9), and mean ECV was 50±14%. SUVR and ECV had good correlation (r=0.61, p<0.001). 124I-evuzamitide myocardial SUVR correlated with measures of cardiac structure and function on CMR including LV wall thickness, mass, and volumes, but not LVEF or stroke volume, Table.
Conclusion: 124I-evuzamitide myocardial SUVR, a novel PET-based measure of amyloid load, had a correlation coefficient of 0.6 with ECV, suggesting commonalities and differences in the composition of what they measure. Further studies are needed to elucidate the best surrogate measure for cardiac amyloid load, particularly for longitudinal monitoring of cardiac amyloid load in response to therapy.



**Author Listing - Lead/ Submitting Author (we will be communicating with this individual): Name, Institution, City and State where the work was done. Co-authors will be added in a separate section.**
Morris Kim, MD
Knight Cardiovascular Institute, Oregon Health & Science University (OHSU)
Portland, OR

**Main Body of the Abstract**
**Introduction:** Cardiac magnetic resonance imaging (CMR) allows for the assessment of cardiac structure, function, and surrogates of amyloid load such as extracellular volume fraction (ECV). 124I-evuzamitide (AT-01) is a novel pan-amyloid PET radiotracer. We investigated the relationship between 124I-evuzamitide myocardial uptake, ECV, and other measures of cardiac structure and function.
**Methods:** Cardiac amyloidosis was diagnosed by standard clinical, laboratory, biopsy, and imaging criteria. All subjects underwent hybrid cardiac PET/MRI with 124I-evuzamitide (mean dose 1.05±0.02 mCi). Traditional measures of cardiac structure and function were assessed on CMR. 124I-evuzamitide uptake was quantified using LV SUVR (ratio of LV myocardium SUV/LV blood pool SUV).
**Results:** We enrolled 50 patients (28 ATTR, 12 AL and 10 without systemic amyloidosis, mean age 72±9.1, 74% male, 82% ≥ NYHA class II). Median 124I-evuzamitide LV SUVR was 1.7 (1.1, 1.9), and mean ECV was 50±14%. SUVR and ECV had good correlation (r=0.61, p<0.001). 124I-evuzamitide myocardial SUVR correlated with measures of cardiac structure and function on CMR including LV wall thickness, mass, and volumes, but not LVEF or stroke volume, Table.
**Conclusion:** 124I-evuzamitide myocardial SUVR, a novel PET-based measure of amyloid load, had a correlation coefficient of 0.6 with ECV, suggesting commonalities and differences in the composition of what they measure. Further studies are needed to elucidate the best surrogate measure for cardiac amyloid load, particularly for longitudinal monitoring of cardiac amyloid load in response to therapy**.**



Relationship Between Myocardial 124I-evuzamitide Uptake and Extracellular Volume Fraction: A Cardiac PET/MRI Study PB123 (#424)

We invite you to attend the XIX International Symposium on Amyloidosis to be held in Rochester, MN.

This symposium is organized as a hybrid meeting (with the focus on in-person) held from Sunday, May 26 through Thursday, May 30, 2024.

Together with the ISA Board and members of Mayo Clinic, a very attractive scientific hybrid program is being planned. The program will cover a variety of types of systemic amyloidosis: ATTR (hereditary and wild-type), AL (light-chain), AA and less frequent forms. There will be key lectures, specific symposia including those company sponsored, oral presentations and poster sessions of accepted abstracts.

COURSE DESCRIPTION
This program will provide a comprehensive review of state-of-the-art education in systemic amyloidosis: basic science, pathophysiology, diagnosis, current and emerging treatments. Scientific presentations will include competitive oral and poster abstracts. The rapid evolution of scientific discovery and expanding treatment options has created tremendous interest in the field and this meeting will fill and important gap in educating scientists and clinicians.