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

• Published in: Journal of nuclear cardiology Vol. 29; no. 2; pp. 741 - 749
• Main Authors: Andrews, Jack P.M., Trivieri, Maria Giovanni, Everett, Russell, Spath, Nicholas, MacNaught, Gillian, Moss, Alastair J., Doris, Mhairi K., Pawade, Tania, van Beek, Edwin J.R., Lucatelli, Christophe, Newby, David E., Robson, Philip, Fayad, Zahi A., Dweck, Marc R.
• Format: Journal Article
• Language: English
• Published: Cham Elsevier Inc 01-04-2022; Springer International Publishing; Springer Nature B.V
• Subjects: 18F-fluoride; Amyloid; Amyloidosis - diagnostic imaging; Aortic stenosis; Aortic Valve Stenosis - diagnostic imaging; Cardiology; Cardiomyopathies; CMR; Contrast Media; Fluorides; Gadolinium; Humans; Imaging; Magnetic Resonance Imaging; Medicine; Medicine & Public Health; Nuclear Medicine; Original; Original Article; PET; PET/MR; Positron-Emission Tomography; Prospective Studies; Radiology; New York; United States > US; Aortic stenosis; 99mTc-DPD; PET/MR; CMRA; TAVI; SPECT; AUC; 18F-fluoride; ANOVA; Amyloid; MGUS; ROC; SUVMEAN; SUVMAX; CMR; OSEM; AL; LGE; 99mTc-HMDP; ATTR; 99mTc-PYP; VOI; GRE; TBRMEAN; MBq; PET; TBRMAX
• ISSN: 1071-3581; 1532-6551
• DOI: 10.1007/s12350-020-02356-1

Cardiac MR is widely used to diagnose cardiac amyloid, but cannot differentiate AL and ATTR subtypes: an important distinction given their differing treatments and prognoses. We used PET/MR imaging to quantify myocardial uptake of 18F-fluoride in ATTR and AL amyloid patients, as well as participants with aortic stenosis and age/sex-matched controls.
In this prospective multicenter study, patients were recruited in Edinburgh and New York and underwent 18F-fluoride PET/MR imaging. Standardized volumes of interest were drawn in the septum and areas of late gadolinium enhancement to derive myocardial standardized uptake values (SUV) and tissue-to-background ratio (TBRMEAN) after correction for blood pool activity in the right atrium.
53 patients were scanned: 18 with cardiac amyloid (10 ATTR and 8 AL), 13 controls, and 22 with aortic stenosis. No differences in myocardial TBR values were observed between participants scanned in Edinburgh and New York. Mean myocardial TBRMEAN 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), and those with AL amyloid (0.96 ± 0.08, P = .01). TBRMEAN values within areas of late gadolinium enhancement provided discrimination between patients with ATTR (1.36 ± 0.23) and all other groups (e.g., AL [1.06 ± 0.07, P = .003]). A TBRMEAN threshold >1.14 in areas of LGE demonstrated 100% sensitivity (CI 72.25 to 100%) and 100% specificity (CI 67.56 to 100%) for ATTR compared to AL amyloid (AUC 1, P = .0004).
Quantitative 18F-fluoride PET/MR imaging can distinguish ATTR amyloid from other similar phenotypes and holds promise in improving the diagnosis of this condition.