Sina Houshmand MD, Abstract Co-Author: Nothing to Disclose

Ali Salavati MD, MPH, Presenter: Nothing to Disclose

Yousi Oquendo, Abstract Co-Author: Nothing to Disclose

Jeffrey H Chudakoff, Abstract Co-Author: Nothing to Disclose

Saeid Gholami MD, Abstract Co-Author: Nothing to Disclose

Thomas J. Werner, Abstract Co-Author: Nothing to Disclose

Abass Alavi MD, Abstract Co-Author: Nothing to Disclose

Several techniques have been used for the measurement of atherosclerosis in major vessels, the majority of these methods require manual delineation of the region of interest (ROI), and therefore, measurements are prone to reader variability. In this study we assess inter-reader variability of different FDG uptake measures.

Twelve FDG-PET/CT scans were included. ROIs were placed around the aorta wall in every slice (3 mm). Three trained readers independently quantified the FDG uptake in aorta by calculating average SUVmean, average SUVmax, and weighted average SUV mean (wA-SUVmean) [∑ (SUVmean x surface area x thickness) / ∑volume]. Intra-class correlation coefficient (ICC), and coefficient of variation (COV) was calculated to measure the reproducibility of these indices.

Comparisons between three readers showed a robust agreement for SUVmean (ICC: 0.99, 95% CI 0.997-0.999; COV: 1.3%), wA-SUVmean (ICC: 0.99, 95%CI: 0.997-0.999; COV: 1.2%) and SUVmax (ICC: 0.93,95% CI: 0.82-0.98; COV: 11%) among three readers. In segment-based comparison, wA-SUVmean had the highest level of agreement (ICC:0.99, 95%CI: 0.96-0.99; COV 9%) and SUVmax had the ICC of 0.92 (95%CI: 0.89-0.94; COV 3.4%) in ascending aorta .Thoracic aorta and aortic arch were similar to thoracic aorta.

In this study, SUVmean and wA-SUVmean, had the strongest inter-reader reliability for quantification of FDG uptake in aortic wall. Therefore, we suggest using these indices for forthcoming studies; particularly ones related to treatment response assessment since the difference between before and after treatment FDG uptake values are of special importance in them.

Optimization of methods for quantification of FDG uptake in major vessel wall enables physician compare therapeutic effect of different lipid lowering drugs more accurately.

Houshmand, S, Salavati, A, Oquendo, Y, Chudakoff, J, Gholami, S, Werner, T, Alavi, A, Quantification of Vessel Wall Inflammation by FDG-PET/CT: An Inter-reader Agreement Assessment Study.  Radiological Society of North America 2014 Scientific Assembly and Annual Meeting, - ,Chicago IL. http://archive.rsna.org/2014/14016809.html