Texture Indices of 18F-FDG PET/CT for Differentiating Squamous Cell Carcinoma and Non-Hodgkin's Lymphoma of the Oropharynx.

We assessed the role of 18F-FDG PET/CT texture indices for the differentiation of squamous cell carcinoma (SCC) and non-Hodgkin's lymphoma (NHL) in the oropharynx. 18F-FDG PET/CT data for 27 patients with SCC and 25 patients with NHL in the oropharynx were investigated. The maximum standardized uptake value (SUVmax), metabolic tumor volume (MTV), total lesion glycolysis (TLG), and six texture indices (homogeneity, entropy, short-run emphasis, long-run emphasis, low gray-level zone emphasis [LGZE], and high graylevel zone emphasis [HGZE]) were derived from PET images. PET/CT parameters of the SCC patients were compared with those of the NHL patients. The diagnostic accuracy of the indices for differentiating SCC from NHL was calculated by a receiver operating characteristic curve analysis. 18F-FDG uptake in the oropharynx was observed in all of the patients. The SUVmax, MTV, and TLG did not differ significantly between the SCC and NHL groups, but two of the six texture indices (LGZE [p=0.004] and HGZE [p=0.03]) showed significant differences between the groups. LGZE was the best discriminative index for the differentiation of SCC and NHL (55.6% sensitivity, 88.0% specificity). The LGZE and HGZE texture indices derived from 18F-FDG PET/CT images may be useful in differentiating SCC and NHL in the oropharynx.

Texture indices of 4'-[methyl-11C]-thiothymidine uptake predict p16 status in patients with newly diagnosed oropharyngeal squamous cell carcinoma: comparison with 18F-FDG uptake.

BACKGROUND: In oropharyngeal squamous cell carcinoma (OPSCC), human papillomavirus (HPV)/p16 status is important as a prognostic biomarker. PURPOSE: We evaluated the relationship between 4'-[methyl-11C]-thiothymidine (11C-4DST) and 18F-FDG PET texture indices and p16 status in patients with newly diagnosed OPSCC. METHODS: We retrospectively reviewed the collected data of 256 consecutive, previously untreated patients with primary head and neck tumors enrolled between November 2011 and October 2019. Complete data on both 11C-4DST and 18F-FDG PET/CT studies before therapy, patients with OPSCC, and p16 status were available for 34 patients. Six of them were excluded because they did not exhibit sufficient 11C-4DST and/or 18F-FDG tumor uptake to perform textural analysis. Finally, 28 patients with newly diagnosed OPSCC were investigated. The maximum standardized uptake value (SUVmax) and 6 texture indices (homogeneity, entropy, short-run emphasis, long-run emphasis, low gray-level zone emphasis, and high gray-level zone emphasis) were derived from PET images. The presence of p16 expression in tumor specimens was examined by immunohistochemistry and compared with the PET parameters. RESULTS: Using 11C-4DST, the expression of p16 was associated with a higher homogeneity (P = 0.012), lower short-run emphasis (P = 0.005), higher long-run emphasis (P = 0.009), and lower high-gray-level-zone emphasis (P = 0.042) values. There was no significant difference between 18F-FDG PET parameters and p16 status. CONCLUSION: Texture indices of the primary tumor on 11C-4DST PET, but not 18F-FDG PET, may be of value in predicting the condition's p16 status in patients with newly diagnosed OPSCC.