Evolving role of cardiac magnetic resonance in cardiac amyloidosis

Table 3 Simplified educational diagnostic and monitoring pathway incorporating cardiac magnetic resonance

Step	CMR finding	Next step
1 Unexplained LVH/HFpEF	Concentric LVH, reduced strain, small pericardial effusion	Proceed to tissue characterization
2 Tissue characterization	Diffuse subendocardial/transmural LGE + elevated native T1/ECV	High suspicion for cardiac amyloidosis
3 Subtype triage	Bone-avid tracer scintigraphy (Tc-99m PYP/DPD/HMDP) + serum/urine free light chains	Grade 2-3 uptake + negative clonal screen = ATTR (no biopsy needed); any clonal positivity requires hematologic work-up ± biopsy
4 Baseline severity/prognosis	Quantify ECV, LGE extent, strain, NT-proBNP/troponin	Risk-stratify and stage per ATTR or AL staging systems
5 Therapy and follow-up	Serial CMR (ECV) on disease-modifying therapy	Track treatment response; stable/falling ECV favors disease stabilization

CMR: Cardiac magnetic resonance; LVH: Left ventricular hypertrophy; HFpEF: Heart failure with preserved ejection fraction; LGE: Late gadolinium enhancement; ECV: Extracellular volume; ATTR: Transthyretin amyloidosis; Tc-99m: Technetium-99m; PYP: ^99mTc-pyrophosphate; DPD: 3,3-diphosphono-1,2-propanodicarboxylic acid; HMDP: Hydroxymethylene diphosphonate; NT-proBNP: N-terminal pro-B-type natriuretic peptide.