Analysis of MRI radiomic features of hypoxic area in nasopharyngeal carcinoma patients

Objective: To analyze the magnetic resonance imaging (MRI) radiomic performance of hypoxic area in nasopharyngeal carcinoma patients, aiming to provide a reference for identification and analysis of hypoxic area. Methods: The MRI-T₁, MRI-T₂, MRI-T₁+ and PET/CT images of 32 patients initially diagnosed with nasopharyngeal carcinoma were retrospectively analyzed. The gross tumor volume (GTV) of nasopharynx was contoured and the hypoxic areas (GTV-H) were identified by ¹⁸F-FMISO-PET images. The non-hypoxic areas (GTV-NH) were defined as the rest of areas removed GTV-H from GTV. The radiomic features of GTV-H and GTV-NH were extracted and compared. Results: The average volume of GTV-H and GTV-NH was (10.92 ± 11.02) cm³ and (7.21 ± 5.70) cm³, respectively. The maximum rate of change was 46% for intensity direct-global min (ID-GM) on MRI-T₁ (P < 0.05, AUC > 0.7 and Youden index > 0.5). The average rate of change was 136% for long run emphasis (LRE), long run high gray level emphasis (LRHGLE) and long run low gray level emphasis (LRLGLE) on MRI-T₂ (P < 0.05, AUC > 0.7 and Youden index > 0.5). The high change rates was greater than 90% on MRI-T₁+ (P < 0.05, AUC > 0.7 and Youden index > 0.5) for ID-GM, LRE, LRHGLE and LRLGLE. Conclusions: The hypoxic area of tumor target can be reflected by MRI radiomics on T₁/T₂/T₁+. Quantifying and tracking the variations of these features can bring benefit to recognize the hypoxic area of nasopharyngeal carcinoma tumor target. (authors)