01 Oct 20. Featured Paper

18F-fluoride PET/MR in cardiac amyloid: a comparison study with aortic stenosis & age- & sex-matched controls.

Link to paper on Journal of Nuclear Cardiology

Authors

Jack P. M. Andrews, Maria Giovanni Trivieri, Russell Everett, Nicholas Spath, Gillian MacNaught, Alastair J. Moss, Mhairi K. Doris, Tania Pawade, Edwin J. R. van Beek, Christophe Lucatelli, David E. Newby, Philip Robson, Zahi A. Fayad, & Marc R. Dweck 

Abstract

Objectives: Cardiac MR is widely used to diagnose cardiac amyloid, but cannot differentiate AL & ATTR subtypes: an important distinction given their differing treatments & prognoses.

We used PET/MR imaging to quantify myocardial uptake of 18F-fluoride in ATTR & AL amyloid patients, as well as participants with aortic stenosis & age/sex-matched controls.

Methods: In this prospective multicenter study, patients were recruited in Edinburgh & New York & underwent 18F-fluoride PET/MR imaging.

Standardized volumes of interest were drawn in the septum & areas of late gadolinium enhancement to derive myocardial standardized uptake values (SUV) & tissue-to-background ratio (TBR_MEAN) after correction for blood pool activity in the right atrium.

Results: 53 patients were scanned: 18 with cardiac amyloid (10 ATTR & 8 AL), 13 controls, & 22 with aortic stenosis.

No differences in myocardial TBR values were observed between participants scanned in Edinburgh & New York.

Mean myocardial TBR_MEAN values in ATTR amyloid (1.13 ± 0.16) were higher than controls (0.84 ± 0.11, P = .0006), aortic stenosis (0.73 ± 0.12, P < .0001), & those with AL amyloid (0.96 ± 0.08, P = .01).

TBR_MEAN values within areas of late gadolinium enhancement provided discrimination between patients with ATTR (1.36 ± 0.23) & all other groups (e.g., AL [1.06 ± 0.07, P = .003]).

A TBR_MEAN threshold >1.14 in areas of LGE demonstrated 100% sensitivity (CI 72.25 to 100%) & 100% specificity (CI 67.56 to 100%) for ATTR compared to AL amyloid (AUC 1, P = .0004).

Conclusion: Quantitative 18F-fluoride PET/MR imaging can distinguish ATTR amyloid from other similar phenotypes & holds promise in improving the diagnosis of this condition.

Keywords

• 18F-fluoride
• Amyloid
• Aortic stenosis
• CMR
• PET
• PET/MR