Reproducibility of ¹⁸F-FDG and 3′-Deoxy-3′-¹⁸F-Fluorothymidine PET Tumor Volume Measurements

Abstract

The objective of this study was to establish the repeatability and reproducibility limits of several volume-related PET imagederived indices-namely tumor volume (TV), mean standardized uptake value, total glycolytic volume (TGV), and total proliferative volume (TPV)-relative to those of maximum standardized uptake value (SUV max ), commonly used in clinical practice. Methods: Fixed and adaptive thresholding, fuzzy C-means, and fuzzy locally adaptive Bayesian methodology were considered for TV delineation. Double-baseline 18 F-FDG (17 lesions, 14 esophageal cancer patients) and 39-deoxy-39-18 F-fluorothymidine ( 18 F-FLT) (12 lesions, 9 breast cancer patients) PET scans, acquired at a mean interval of 4 d and before any treatment, were used for reproducibility evaluation. The repeatability of each method was evaluated for the same datasets and compared with manual delineation. Results: A negligible variability of less than 5% was measured for all segmentation approaches in comparison to manual delineation (5%-35%). SUV max reproducibility levels were similar to others previously reported, with a mean percentage difference of 1.8% 6 16.7% and 20.9% 6 14.9% for the 18 F-FDG and 18 F-FLT lesions, respectively. The best TV, TGV, and TPV reproducibility limits ranged from 221% to 31% and 230% to 37% for 18 F-FDG and 18 F-FLT images, respectively, whereas the worst reproducibility limits ranged from 290% to 73% and 268% to 52%, respectively. Conclusion: The reproducibility of estimating TV, mean standardized uptake value, and derived TGV and TPV was found to vary among segmentation algorithms. Some differences between 18 F-FDG and 18 F-FLT scans were observed, mainly because of differences in overall image quality. The smaller reproducibility limits for volumederived image indices were similar to those for SUV max , suggesting that the use of appropriate delineation tools should allow the determination of tumor functional volumes in PET images in a repeatable and reproducible fashion.

Robustness of intratumour 18F-FDG PET uptake heterogeneity quantification for therapy response prediction in oesophageal carcinoma

“…This probability is calculated by taking into account the voxel's intensity with respect to the statistical distributions (characterized by their mean and variance) of the voxels in the various regions of the image, as well as its spatial correlation with neighboring voxels in 3D. This approach has been previously validated on simulated and clinical datasets showing high combined accuracy, robustness and reproducibility, for the delineation of both homogeneous and heterogeneous MATVs [30][31][32].…”

Adaptive threshold segmentation of pituitary adenomas from FDG PET images for radiosurgery

“…Inter‐ and intraobserver variability in the target delineating has been reported and variability also was largely affected by the experience of the clinician. This process is also quite slow and has poor reproducibility (1) . PET images are susceptible to variations in window level settings, 2 , 3 , 4 and changing the intensity of the images or the color scale dramatically changes the perception of the volume of the target (5) .…”

Fuzzy Multi-class Statistical Modeling for Efficient Total Lesion Metabolic Activity Estimation from Realistic PET Images

“…SUV max (maximum lesion activity uptake), SUV mean (average lesion activity uptake), SUV peak (activity uptake in 1cc spherical region of interest (ROI) around the SUV max ) [12], TLV (total lesion volume) and TLA (total lesion activity uptake) or TLG (total lesion glycolysis), in the context of 18 F-FDG PET, are some of them. However, TLA was found to be clinically relevant in [3,7]. TLA calculation typically involves tumor delineation, to find TLV, followed by the quantification TLA = SUV mean × TLV.…”

“…PET images are typically normalized for injected dose and patient weight to a scale known as the standardized uptake value (SUV) in g/mL. Several PET derived markers [3,7,12] have been used in the literature for the longitudinal evaluation of tumor proliferation. SUV max (maximum lesion activity uptake), SUV mean (average lesion activity uptake), SUV peak (activity uptake in 1cc spherical region of interest (ROI) around the SUV max ) [12], TLV (total lesion volume) and TLA (total lesion activity uptake) or TLG (total lesion glycolysis), in the context of 18 F-FDG PET, are some of them.…”