Non-Invasive Diagnostic Algorithm in Transthyretin Cardiac Amyloidosis: Is Bone Scintigraphy Always Enough?

Technetium-99m bone scintigraphy has revolutionized the non-invasive diagnosis of transthyretin cardiac amyloidosis (ATTR-CM) and markedly increased disease recognition. Although this technique should ideally be applied in patients with a high pre-test probability of ATTR-CM, its use in other clinical settings may reveal incidental pathological myocardial uptake that prompts referral to specialized centers even in the absence of typical red flags. In such cases, where confounding factors such as left ventricular hypertrophy from alternative causes may coexist, awareness of potential pitfalls and the integration of scintigraphic findings with clinical features, biomarkers, and echocardiographic data are essential to avoid misdiagnosis and inappropriate therapy. Cardiac magnetic resonance (CMR) imaging provides a crucial complementary role, offering refined tissue characterization, improved differential diagnosis, and valuable prognostic insights. A combined approach that situates scintigraphy within the broader clinical context and incorporates CMR in ambiguous cases is fundamental to ensure an accurate diagnosis and optimal patient management.