Accurate analysis and visualization of cardiac ¹¹C-PIB uptake in amyloidosis with semiautomatic software

¹¹C-PIB PET is a promising non-invasive diagnostic tool for cardiac amyloidosis. Semiautomatic analysis of PET data is now available but it is not known how accurate these methods are for amyloid imaging. The aim of this study was to evaluate the feasibility of one semiautomatic software tool for analysis and visualization of ¹¹C-PIB left ventricular retention index (RI) in cardiac amyloidosis.

Patients with systemic amyloidosis and cardiac involvement (n = 10) and healthy controls (n = 5) were investigated with dynamic ¹¹C-PIB PET. Two observers analyzed the PET studies with semiautomatic software to calculate the left ventricular RI of ¹¹C-PIB and to create parametric images. The mean RI at 15-25 min from the semiautomatic analysis was compared with RI based on manual analysis and showed comparable values (0.056 vs 0.054 min⁻¹ for amyloidosis patients and 0.024 vs 0.025 min⁻¹ in healthy controls; P = .78) and the correlation was excellent (r = 0.98). Inter-reader reproducibility also was excellent (intraclass correlation coefficient, ICC > 0.98). Parametric polarmaps and histograms made visual separation of amyloidosis patients and healthy controls fast and simple.

Accurate semiautomatic analysis of cardiac ¹¹C-PIB RI in amyloidosis patients is feasible. Parametric polarmaps and histograms make visual interpretation fast and simple.