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

Area of Science:

• Nuclear Medicine
• Cardiology
• Radiopharmaceuticals

Background:

• Cardiac amyloidosis (CA) is a progressive disease.
• Accurate and early diagnosis of transthyretin amyloid CA (ATTR-CA) is crucial for patient management.
• Current diagnostic methods can be invasive or time-consuming.

Purpose of the Study:

• To identify reliable indexes for detecting cardiac amyloidosis (CA) using 99mTc-HMDP planar scintigraphy.
• To determine the earliest acquisition time for accurate diagnosis of ATTR-CA.

Main Methods:

• Analysis of dynamic planar scintigraphy images of the anterior thorax after 99mTc-HMDP injection in 38 patients (18 ATTR-CA, 20 controls).
• Calculation of time/activity curves (TAC) and derived indexes (TAC_Heart/Bone(t), RI_heart-bone(t)) from various regions of interest.
• Evaluation of diagnostic performance using area under the curve (AUC) analysis.

Main Results:

• Indexes TAC_Heart/Bone(t) and RI_heart-bone(t) effectively distinguished ATTR-CA patients from controls for t > 6 minutes.
• AUC values of 0.9 were achieved at approximately 6 minutes post-injection.
• AUC values approached 1 for acquisition times greater than 10 minutes.

Conclusions:

• The proposed scintigraphy method provides an inexpensive and efficient way to detect ATTR-CA.
• Early detection of ATTR-CA is feasible using 99mTc-HMDP scintigraphy as early as 6 minutes post-injection.