Molecular imaging of TTR amyloidosis: New data

Transthyretin cardiac amyloidosis (ATTR CM) is a recognized cause of heart failure that results from age related or hereditary transthyretin misfolding and systemic amyloid deposition. It is characterized by clinical heterogeneity and may affect the heart among peripheral and autonomous nervous system, gastrointestinal tract, kidneys and eyes. Technetium 99m bone avid scintigraphy with standardized planar and SPECT/CT protocols, interpreted using Perugini grading and heart to contralateral lung ratios after exclusion of light chain amyloidosis, enables highly sensitive, non invasive diagnosis of ATTR CM and early detection in at risk individuals. This narrative review synthesizes recent data on molecular imaging, emphasizing the central role of nuclear medicine physicians in applying multimodality diagnostic algorithms, recognizing typical and equivocal scan patterns. It further explores emerging roles for quantitative SPECT/CT and amyloid PET tracers in monitoring response to disease modifying therapies, including tetramer stabilizers (tafamidis, acoramidis), RNA interference silencers (vutrisiran, patisiran), and investigational fibril targeting antibodies and gene editing strategies, underscoring a shift from purely diagnostic imaging toward dynamic treatment monitoring in ATTR CM.