Room: Room 205
Purpose: The propose of this study is to analyze the manifestation of MRI radiomic features of hypoxia target for nasopharyngeal carcinoma (NPC), which could provide a reference for identification and analysis of hypoxia target area.
Methods: The MRI and PET/CT images of 32 patients with NPC were analyzed. Gross tumor volume of nasopharynx (GTVnx) were countoured, and the hypoxic areas (GTV-H) were identified by PET images. The non-hypoxic areas (GTV-NH) were defined as the rest of areas removed GTV-H from GTVnx. The radiomics features of GTV-H and GTV-NH were extracted from MRI-T1, MRI-T2, MRI-T1 contrast (T1+) images and the differences were compared.
Results: (1) The average volume of GTV-H and GTV-NH was 10.92Â±11.02cmÂ³ and 7.21Â±5.70 cmÂ³, respectively. There was no significant correlation between the volume and hypoxia status. (2) 22 statistically significant different features were observed on MRI-T1 (AUC>0.7 and Youden index >0.5). Intensity Direct -Global Min had the maximum variation rate with 45.55%. (3) 3 statistically significant different features were observed on MRI-T2 (AUC>0.7 and Youden index >0.5). The average variation rate for those 3 features (Gray Level Run Length Matrix, GLRLM) was 136%. (4) 4 statistically significant different features were observed on MRI-T1+ (AUC>0.7 and Youden index >0.5). The variation rate were all greater than 90% for these 4 features (3 in GLRLM and 1 in Intensity Direct).
Conclusion: The hypoxia tumor target can be reflected by MRI radiomics features on T1/T2/T1+ images. Quantifying and tracking the variation of these features can be help to recognize the hypoxia area of NPC tumor target, which will be useful to achieve the simultaneous integrated boost radiation therapy for NPC.