Role of [99mTc]Tc-DPD gated-SPECT-CT in the assessment of myocardial uptake patterns in transthyretin amyloidosis (TTR-CA).

PURPOSE: To evaluate the feasibility of identifying various distribution patterns of [99mTc]Tc-DPD in patients with cardiac transthyretin amyloidosis using gated SPECT-CT.

MATERIALS AND METHODS: Gated SPECT-CT was performed in patients with a positive scintigraphy result for cardiac amyloidosis due to transthyretin (TTR-CA). Patients were categorized into several groups based on sex, degree of radiopharmaceutical uptake according to the Perugini's visual scale and ventricular ejection fraction (LVEF). Cardiac polar maps were obtained using Emory Cardiac Toolbox™ software and scored by segments according to radiopharmaceutical uptake on a scale from 0 (no uptake) to 4 (very high uptake intensity). The Mann-Whitney U and Pearson's Chi-square statistical tests were employed to identify significant differences in distribution patterns according to the different variables under study.

RESULTS: 65 patients were evaluated. The gender variable determined the main statistically significant differences, highlighting distinct distribution patterns of the radiopharmaceutical at the cardiac level: while women showed lower accumulation of [99mTc]Tc-DPD in the middle anterior (p=0.035) and basal anterior (p=0.001) segments, whereas men demonstrated higher accumulation in the basal anteroseptal (p=0.009) and basal inferoseptal (p=0.009) segments, and lower scores in the lateroapical segment (p=0.039).

CONCLUSIONS: Gated SPECT-CT is an essential tool for assessing the distribution pattern of [99mTc]Tc-DPD of patients with TTR-CA, offering valuable insights into the pathophysiology of the disease.