Cardiac amyloidosis detection by early bisphosphonate (99mTc-HMDP) scintigraphy

Objective To determine one or more indexes able to detect the presence of cardiac amyloidosis (CA) from planar scintigraphy images after injection of 99mTc-HMDP tracer and to identify the earliest acquisition time able to ensure an accurate diagnosis of amyloid transthyretin CA. Methods and Results A total of 38 patients were included: 18 subjects with a final diagnosis of ATTR-CA and 20 controls. Dynamic planar images of the anterior thorax were acquired, starting at intravenous injection of approximate to 700 MBq of 99mTc-HMDP. From time/activity curves (TAC) of regions of interest such as heart, vascular region, right ribcage, and soft tissues, several indices were considered. From the analysis, it resulted that both TAC(Heart/Bone)(t) and RIheart-bone(t), fort > 6 minutes, well distinguish ATTR-CA patients from controls subjects. This is confirmed by the area under curves (AUC) analysis giving AUC values =.9 att approximately equal to 6 minutes and AUC approximately equal to 1 fort > 10 minutes. Conclusions The method proposed allows determining the presence of ATTR-CA, in an inexpensive manner both in terms of examination costs and time spent.