Jun Zhang PhD, Presenter: Nothing to Disclose

Nathan C. Hall MD, PhD, Abstract Co-Author: Consultant, Enlyton Ltd Corporation

Steffen Sammet MD, PhD, Abstract Co-Author: Nothing to Disclose

Ricky R. Layman MS, Abstract Co-Author: Nothing to Disclose

Michael Vinzenz Knopp MD, PhD, Abstract Co-Author: Nothing to Disclose

To assess the impact of ROI/VOI placement on quantification of Standardized Uptake Value (SUV) and Metabolic Active Tumor Volume (matV) in FDG PET

Different ROI/VOI tools, I) 1D pixel-lense; II) exterior outlining based approaches including 2D (rectangle, circle, ellipse, free hand & isocontour) and 3D (box, sphere, ellipsoid, isosurface); and III) interior growing based approaches including 2D and 3D region-grow & isocontour were assessed using commercial workstations (Siemens Leonardo, GE AW, Philips EBW, MIMVista) and in-house developed software. An advanced 4D isosurface fusion tool was developed for ROI/VOI effectiveness validation. 50 target lesions of various sizes, shapes, heterogeneity and anatomical region were used for evaluation and quantification as well as advantages and disadvantages of the tools compared

For tumor SUVmax and matV, 3D VOI approaches show the advantages of high efficiency and convenience. The developed rotated ROI/VOI tools revealed a significant improvement (p>0.01) for accuracy of ROI/VOI placement compared to those without a rotation functionality. We found that 3D VOI approaches can lead to false representations of the true SUV and matV by including additional tumors/hot areas that might not be seen in current MPR view approach

As quantification is gaining increasing importance in PET for characterization and response assessement, the approach for ROI/VOI placement is of importance as it substantially impact the results. Most current ROI/VOI tools have limitations when dealing with heterogenous and non cyclindrical tumors thus potentially leading ti inaccurate quantification. We found that an advanced VOI approaches with rotation and isocontour integration marketly improves the accuracy and robustness

As quantification is on increasing importanct especially for response assessement, limitations in ROI/VOI methodologies need to be understood and most robust approaches should be utilized.

Zhang, J, Hall, N, Sammet, S, Layman, R, Knopp, M, The Impact of ROI/VOI Placement on Quantification in 18F-FDG PET/CT.  Radiological Society of North America 2009 Scientific Assembly and Annual Meeting, November 29 - December 4, 2009 ,Chicago IL. http://archive.rsna.org/2009/8014505.html