Cardiac PET in Amyloidosis Diagnosis

Cardiac PET imaging plays an increasingly important role in diagnosing infiltrative cardiomyopathies. FDG PET demonstrates active inflammation in cardiac sarcoidosis while Tc99m PYP scintigraphy identifies transthyretin amyloidosis with high sensitivity and specificity. These modalities have transformed diagnostic algorithms reducing reliance on endomyocardial biopsy.

FDG PET requires specific patient preparation including eighteen hour carbohydrate restriction and high fat meal to suppress physiologic myocardial glucose uptake allowing identification of inflammatory foci. Pattern recognition includes focal or focal on diffuse uptake suggesting active sarcoidosis. Hybrid PET MR imaging combines functional metabolic and structural assessment in a single session improving diagnostic accuracy and treatment planning.

Tc99m PYP scintigraphy diagnoses transthyretin amyloidosis with grade two or three uptake on planar imaging combined with absent monoclonal protein. Heart to contralateral lung ratio above one point five at one hour confirms ATTR amyloidosis. The technique avoids endomyocardial biopsy in many patients. Treatment response monitoring uses serial imaging with FDG uptake reduction in sarcoidosis indicating immunosuppressive efficacy and stabilization of cardiac biomarkers in ATTR. Multimodal evaluation with PET MR and echocardiography optimizes diagnosis and management.