To explore the relationship of a new PET image parameter, 18F-fluorodeoxyglucose (18F-FDG) uptake heterogeneity assessed by texture analysis, with maximum standardized uptake value (SUVmax) and tumor TNM staging.
Materials and methods
Forty consecutive patients with esophageal squamous cell carcinoma were enrolled. All patients underwent whole-body preoperative 18F-FDG PET/CT. Heterogeneity of intratumoral 18F-FDG uptake was assessed on the basis of the textural features (entropy and energy) of the three-dimensional images using MATLAB software. The correlations between the textural parameters and SUVmax, histological grade, tumor location, and TNM stage were analyzed.
Tumors with higher SUVmax were seen to be more heterogenous on 18F-FDG uptake. Significant correlations were observed between T stage and SUVmax (rs=0.390, P=0.013), entropy (rs=0.693, P<0.001), and energy (rs=−0.469, P=0.002). Correlations were also found between SUVmax, entropy, energy, and N stage (rs=0.326, P=0.04; rs=0.501, P=0.001; rs=−0.413, P=0.008). The American Joint Committee on Cancer stage correlated significantly with all metabolic parameters. The receiver-operating characteristic curve demonstrated an entropy of 4.699 as the optimal cutoff point for detecting tumors above stage IIb with an areas under the ROC curve of 0.789 (P<0.001).
This study provides initial evidence for the relationship between the new parameter of tumor uptake heterogeneity and the commonly used simplistic parameter of SUV and tumor stage. Our findings suggest a complementary role of these parameters in the staging and prognosis of esophageal squamous cell carcinoma.