Positron emission tomography in the diagnosis and follow-up of transthyretin amyloid cardiomyopathy patients: A systematic review

Purpose: Transthyretin (ATTR) amyloidosis is a progressive protein misfolding disease with frequent cardiac involvement. This review aims to determine the value of PET in diagnosis, assessment of disease progression or treatment response and its relation to clinical outcome in follow-up of ATTR amyloid cardiomyopathy (ATTR-CM) patients. Methods: Medline, Cochrane Library, Embase and Web of Science databases were searched, from the earliest date available until December 2022, for studies investigating the use of PET in ATTR-CM patients. Studies containing original data were included, except for case reports. Risk of bias was assessed by QUADAS-2. Results: Twenty-one studies were included in this systematic review, investigating five different tracers: carbon-11 Pittsburgh compound B ([¹¹C]PIB), fluorine-18 Florbetaben ([¹⁸F]FBB), fluorine-18 Florbetapir ([¹⁸F]FBP), fluorine-18 Flutemetamol ([¹⁸F]FMM) and fluorine-18 Sodium Fluoride (Na[¹⁸F]F). In total 211 ATTR amyloidosis patients were included. A majority of studies concluded that [¹¹C]PIB, [¹⁸F]FBP and Na[¹⁸F]F can distinguish ATTR amyloidosis patients from controls, and that [¹¹C]PIB and Na[¹⁸F]F, but not [¹⁸F]FBP, can distinguish ATTR-CM patients from patients with cardiac light chain amyloidosis. Evidence on the performance of [¹⁸F]FBB and [¹⁸F]FMM was contradictory. No studies on the use of PET in follow-up were found. Conclusion: [¹¹C]PIB, Na[¹⁸F]F and [¹⁸F]FBP can be used to diagnose cardiac amyloidosis, although [¹⁸F]FBP may not be suitable for the distinction of different types of amyloid cardiomyopathy. No studies on PET in the follow-up of ATTR amyloidosis patients were found. Future research should focus on the use of these PET tracers in the follow-up of ATTR amyloidosis patients.