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 countoured 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 0.7 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 0.7 and Youden index>0.5). The high change rates was greater than 90% on MRI-T1+ (P 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. Key words: Nasopharyngeal neoplasm hypoxic area; Radiomics; Hypoxic area identification