Abstract Body (Do not enter title and authors here): Background
Cardiac amyloidosis (CA) leads to restrictive cardiomyopathy, heart failure, and increased thromboembolic risk. This hypercoagulability condition is determined by the mechanical atrial dysfunction associated with blood stasis and by amyloid deposition linked to endothelial dysfunction. The identification of intracardiac thrombosis and coronary artery disease (CAD) in CA patients remains challenging due to the limitations of conventional imaging methods.

Hypothesis
We hypothesize that cardiac computed tomography (CCT) can reliably assess myocardial features, intracardiac thrombosis, and CAD in patients with CA.

Methods
We enrolled patients with a recently confirmed or suspected CA diagnosis and a clinical indication for CCT. Photon-counting detector-computed tomography (PCCT) NAEOTOM Alpha protocol included unenhanced imaging for coronary artery calcium (CAC) score, contrast-enhanced angiography for CAD evaluation, and delayed-phase imaging for thrombosis, late iodine enhancement (LIE), and extracellular volume (ECV) assessment. The ECV quantification was based on late-PCCT scan and iodine images of the myocardium.

Results
A total of 16 adults (14 transthyretin and 2 light chain CA, 87% male, mean age 78 years) were recruited. CCT showed an Agatson score of 329 (mean), with a score 3 in 40%; obstructive CAD was detected in 1 patient (6%, anterior descending artery disease); myocardial bridge in 19%. LIE displayed an ischemic pattern in 1 patient, while in the others there was a diffuse non-ischemic pattern involving both ventricles (66%) and both atria (15%)(figure 1). No intracardiac thrombi were detected. In the recruited population, ECV was 38% at 5 minutes (figure).

Conclusions
CCT may be an effective non-invasive tool for guiding the management of CA, assessing myocardial features like ECV, and LIE, and identifying CAD and structural anomalies in CA patients. It may aid in ruling out cardiac thrombi and support comprehensive patient evaluation, highlighting its potential to guide diagnosis and management in CA patients. Further research is needed to explore the potential role of CCT and the ECV assessment in the diagnostic and therapeutic algorithm of CA.