Imaging-detected extranodal extension in head and neck cancer: clinical implications, diagnostic criteria, and the potential of photon-counting detector CT. - Kuno H; Hiyama T; Sasaki T; Sakashita S; Onaga R; Tomioka T; Muramatsu Y; Akino N; Taguchi H; Sekiya K; Kobayashi T (Japanese journal of radiology, 2026)