**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.**
Awais A. Malik, MD (Mayo Clinic, Jacksonville FL, Department of Cardiology)

**Main Body of the Abstract**
Introduction:
18F-fluorodeoxyglycose(FDG)/13N-ammonia cardiac positron emission tomography/computed tomography (PET/CT) scan is routinely used for diagnostic evaluation and surveillance of inflammatory cardiomyopathies such as cardiac sarcoidosis. We report a case of wild-type transthyretin (TTR) cardiac amyloidosis (CA) with positive 18F-FDG/13N-ammonia cardiac PET/CT.
Case:
85-year-old male with supraventricular tachycardia ablation, non-sustained ventricular tachycardia, non-obstructive coronary artery disease and presumed isolated cardiac sarcoidosis diagnosed 3 years ago (based on delayed gadolinium enhancement on cardiac magnetic resonance imaging and myocardial inflammation with perfusion abnormalities on 18F-FDG/13N-ammonia cardiac PET/CT [Fig:A]) on methotrexate presented for evaluation of fatigue and dyspnea. Physical examination was unremarkable. High sensitivity troponin-T was 39 ng/L (25 ng/L 3 years ago) and NT-proBNP was 1279 pg/mL (268 pg/mL 3 years ago). Electrocardiogram (ECG) showed sinus rhythm with elevated artificial intelligence-enhanced ECG probability for amyloid (0.98 versus 0.34 three years ago; detection threshold >0.48). Repeat 18F-FDG/13N-ammonia cardiac PET/CT demonstrated resolution of myocardial inflammation (Fig:B). Echocardiogram showed normal biventricular chamber size/function but increased concentric left ventricular (LV) wall thickness (18 mm)/mass and decreased LV global longitudinal strain of -16% compared to prior study. These findings raised suspicion for CA leading to a 99mTechnetium Pyrophosphate scan which was strongly suggestive of CA (Fig:C-E). Screening for light chain CA and testing for TTR gene were negative. Methotrexate was discontinued and Tafamidis was started.
Discussion:
Reasons for a positive 18F-FDG/13N-ammonia cardiac PET/CT scan may include underlying inflammation related to pathophysiology of cardiac amyloidosis, difficulty suppressing physiological myocardial 18F-FDG uptake due to amyloid infiltration and/or co-existent inflammatory cardiomyopathy.



**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.**
Awais A. Malik, MD (Mayo Clinic, Jacksonville FL, Department of Cardiology)

**Main Body of the Abstract**
**Introduction:**
18F-fluorodeoxyglycose(FDG)/13N-ammonia cardiac positron emission tomography/computed tomography (PET/CT) scan is routinely used for diagnostic evaluation and surveillance of inflammatory cardiomyopathies such as cardiac sarcoidosis. We report a case of wild-type transthyretin (TTR) cardiac amyloidosis (CA) with positive 18F-FDG/13N-ammonia cardiac PET/CT.
**Case:**
85-year-old male with supraventricular tachycardia ablation, non-sustained ventricular tachycardia, non-obstructive coronary artery disease and presumed isolated cardiac sarcoidosis diagnosed 3 years ago (based on delayed gadolinium enhancement on cardiac magnetic resonance imaging and myocardial inflammation with perfusion abnormalities on 18F-FDG/13N-ammonia cardiac PET/CT [Fig:A]) on methotrexate presented for evaluation of fatigue and dyspnea. Physical examination was unremarkable. High sensitivity troponin-T was 39 ng/L (25 ng/L 3 years ago) and NT-proBNP was 1279 pg/mL (268 pg/mL 3 years ago). Electrocardiogram (ECG) showed sinus rhythm with elevated artificial intelligence-enhanced ECG probability for amyloid (0.98 versus 0.34 three years ago; detection threshold >0.48). Repeat 18F-FDG/13N-ammonia cardiac PET/CT demonstrated resolution of myocardial inflammation (Fig:B). Echocardiogram showed normal biventricular chamber size/function but increased concentric left ventricular (LV) wall thickness (18 mm)/mass and decreased LV global longitudinal strain of -16% compared to prior study. These findings raised suspicion for CA leading to a 99mTechnetium Pyrophosphate scan which was strongly suggestive of CA (Fig:C-E). Screening for light chain CA and testing for TTR gene were negative. Methotrexate was discontinued and Tafamidis was started.
**Discussion:**
Reasons for a positive 18F-FDG/13N-ammonia cardiac PET/CT scan may include underlying inflammation related to pathophysiology of cardiac amyloidosis, difficulty suppressing physiological myocardial 18F-FDG uptake due to amyloid infiltration and/or co-existent inflammatory cardiomyopathy.



Wild-type Transthyretin Cardiac Amyloidosis with Positive 18F-FDG/13N-ammonia Cardiac Positron Emission Tomography PB121 (#418)

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.