Courtesy of Dr Jack Andrews and Prof Marc Dweck, this image shows late gadolinium-enhanced (LGE) cardiac MR images [top row] and corresponding fused 18F-fluoride cardiac MR-PET images [bottom row] comparing radiotracer uptake patterns across four cohorts of study participants in columns from left to right: Age and sex matched controls, patients with aortic stenosis, and patients with cardiac amyloid of two subtypes: amyloid light chain (AL) and amyloidosis transthyretin (ATTR).
Gadolinium-enhanced MR is widely used to diagnose cardiac amyloid, but cannot differentiate AL and ATTR subtypes which are associated with different prognoses and different treatment strategies. A single MR-PET scan enables the accurate diagnosis of cardiac amyloid from MR with clear discrimination of AL and TTR amyloid from 18F-fluoride PET in co-registered images. The mean target to background ratio (TBR) values in the image above demonstrate uptake greater in the blood pool than myocardium for a control subject (E) and a patient with aortic stenosis (F), contrasted with an AL amyloid patient displaying a characteristic distribution of myocardial LGE (C) and patchy myocardial uptake greater than the blood pool (G) whereas a TTR amyloid patient displaying similar LGE findings (D) is distinguished by extensive biventricular uptake (H). These findings show promise for 18F-fluoride cardiac MR-PET imaging in the diagnosis and monitoring of patients with TTR amyloid.
The image is taken from a recently published multicentre study that conducted hybrid 18F-fluoride imaging with participants recruited in Edinburgh and New York, notably one of the first publications of data from the first MR PET system in Scotland (opened in 2017 at Edinburgh Imaging Facility QMRI):
Andrews JPM, Trivieri MG, Everett R, Spath N, MacNaught G, Moss AJ, Doris MK, Pawade T, van Beek EJR, Lucatelli C, Newby DE, Robson P, Fayad ZA, Dweck MR. 18F-fluoride PET/MR in cardiac amyloid: A comparison study with aortic stenosis and age- and sex-matched controls. J Nucl Cardiol 2020.