Assessment of epicardial adipose tissue on virtual non-contrast images derived from photon-counting detector coronary CTA datasets
Franka Risch, Florian Schwarz, Franziska Braun, Stefanie Bette, Judith Becker, Christian Scheurig‐Muenkler, Thomas Kroencke, Josua A. Decker
Abstract
Abstract Objectives To assess epicardial adipose tissue (EAT) volume and attenuation of different virtual non-contrast (VNC) reconstructions derived from coronary CTA (CCTA) datasets of a photon-counting detector (PCD) CT-system to replace true non-contrast (TNC) series. Methods Consecutive patients ( n = 42) with clinically indicated CCTA and coronary TNC were included. Two VNC series were reconstructed, using a conventional (VNC Conv ) and a novel calcium-preserving (VNC PC ) algorithm. EAT was segmented on TNC, VNC Conv , VNC PC , and CCTA (CTA -30 ) series using thresholds of −190 to −30 HU and an additional segmentation on the CCTA series with an upper threshold of 0 HU (CTA 0 ). EAT volumes and their histograms were assessed for each series. Linear regression was used to correlate EAT volumes and the Euclidian distance for histograms. The paired t -test and the Wilcoxon signed-rank test were used to assess differences for parametric and non-parametric data. Results EAT volumes from VNC and CCTA series showed significant differences compared to TNC (all p < .05), but excellent correlation (all R 2 > 0.9). Measurements on the novel VNC PC series showed the best correlation ( R 2 = 0.99) and only minor absolute differences compared to TNC values. Mean volume differences were −12%, −3%, −13%, and +10% for VNC Conv , VNC PC , CTA -30 , and CTA 0 compared to TNC. Distribution of CT values on VNC PC showed less difference to TNC than on VNC Conv (mean attenuation difference +7% vs. +2%; Euclidean distance of histograms 0.029 vs. 0.016). Conclusions VNC PC -reconstructions of PCD-CCTA datasets can be used to reliably assess EAT volume with a high accuracy and only minor differences in CT values compared to TNC. Substitution of TNC would significantly decrease patient’s radiation dose. Key points • Measurement of epicardial adipose tissue (EAT) volume and attenuation are feasible on virtual non-contrast (VNC) series with excellent correlation to true non-contrast series (all R 2 >0.9). • Differences in VNC algorithms have a significant impact on EAT volume and CT attenuation values. • A novel VNC algorithm (VNC PC ) enables reliable assessment of EAT volume and attenuation with superior accuracy compared to measurements on conventional VNC- and CCTA-series.