Effects of Reusing Baseline Volumes of Interest by Applying (Non-)Rigid Image Registration on Positron Emission Tomography Response Assessments

Floris H. P. van Velden, Ida A. Nissen, Wendy Hayes, Linda M. Velasquez, Otto S. Hoekstra, Ronald Boellaard, Xiaoyuan Chen
2014 PLoS ONE  
Objectives: Reusing baseline volumes of interest (VOI) by applying non-rigid and to some extent (local) rigid image registration showed good test-retest variability similar to delineating VOI on both scans individually. The aim of the present study was to compare response assessments and classifications based on various types of image registration with those based on (semi)-automatic tumour delineation. Methods: Baseline (n = 13), early (n = 12) and late (n = 9) response (after one and three
more » ... les of treatment, respectively) whole body [ 18 F]fluoro-2-deoxy-D-glucose positron emission tomography/computed tomography (PET/CT) scans were acquired in subjects with advanced gastrointestinal malignancies. Lesions were identified for early and late response scans. VOI were drawn independently on all scans using an adaptive 50% threshold method (A50). In addition, various types of (non-)rigid image registration were applied to PET and/or CT images, after which baseline VOI were projected onto response scans. Response was classified using PET Response Criteria in Solid Tumors for maximum standardized uptake value (SUV max ), average SUV (SUV mean ), peak SUV (SUV peak ), metabolically active tumour volume (MATV), total lesion glycolysis (TLG) and the area under a cumulative SUV-volume histogram curve (AUC). Results: Non-rigid PET-based registration and non-rigid CT-based registration followed by non-rigid PET-based registration (CTPET) did not show differences in response classifications compared to A50 for SUV max and SUV peak, , however, differences were observed for MATV, SUV mean , TLG and AUC. For the latter, these registrations demonstrated a poorer performance for small lung lesions (,2.8 ml), whereas A50 showed a poorer performance when another area with high uptake was close to the target lesion. All methods were affected by lesions with very heterogeneous tracer uptake. Conclusions: Non-rigid PET-and CTPET-based image registrations may be used to classify response based on SUV max and SUV peak . For other quantitative measures future studies should assess which method is valid for response evaluations by correlating with survival data.
doi:10.1371/journal.pone.0087167 pmid:24489860 pmcid:PMC3904976 fatcat:6r7ox5qscref5n2uieyu54yzb4