The management of transthyretin amyloid cardiomyopathy (ATTR-CM) has revolved around the scintigraphic diagnosis since the introduction of a specific treatment; however, the equivalency of the bone radiotracers remains unclear. This retrospective monocentric observational study compared 99m TcTc-3,3-diphosphono-1,2-propanodicarboxylic acid ( 99m TcTc-DPD) and 99m TcTc-hydroxy-methylene diphosphonate ( 99m TcTc-HMDP) intensity of myocardial uptake compared with background noise for ATTR-CM suspicion. Two hundred and seventy-four patients who underwent planar scintigraphy after intravenous injection of 99m TcTc-DPD or 99m TcTc-HMDP for ATTR-CM were included. The patients’ current visual Perugini grades were retrieved. Regions of interest were measured on the heart (H) and on the contralateral mediastinum (CM), and H/CM ratios were calculated. Although the distribution of quantitative assessments of heart to contralateral mediastinum ratios is wider with 99m TcTc-DPD, no difference in Perugini grades was found between 99m TcTc-DPD and 99m TcTc-HMDP for the diagnosis of ATTR-CM in evocative/non-evocative conditions. There was no difference in ATTR-CM diagnosis between the 2 tracers with a threshold of 1.5 ( p -value <0.001 for 99m TcTc-HMDP and for 99m TcTc-DPD). We show in our local cohort that 99m TcTc-DPD and 99m TcTc-HMDP for amyloidosis diagnosis are equivalent for ATTR-CM diagnosis based on the Perugini grading scale.
Dubois et al. (Sun,) studied this question.