Dual-energy subtraction radiography improves laryngeal delineation in patients with moderate to severe cervical spondylosis

Purpose To investigate the feasibility of dual-energy subtraction (DES) in patients with moderate-severe cervical spondylosis for improving delineation of the larynx on flat panel detector (FPD) radiography. Materials and methods For 118 patients, we graded conventional/DES anterior–posterior views for delineation of the vocal cords, subglottis, and pyriform sinus using a 5-point scale and lateral views from conventional laryngeal FPD radiography to determine cervical spondylosis severity on a scale from 0 (none) to 3 (severe). We compared the delineation of each anatomical structure in both groups of grades 0–1 and grades 2–3 of spondylosis severity between conventional and DES methods and the improved delineation rate for each anatomical structure by DES compared to the conventional method between both groups. Results With DES, the delineation of each anatomical structure was significantly better than with conventional radiography for both groups ( P < 0.0001). The improved delineation rate of the vocal cord and subglottis using DES was significantly higher in grades 2–3 than in grades 0–1 ( P < 0.05), although there was no significant difference in the delineation rate of the pyriform sinus between the groups ( P = 0.847). Conclusion DES provides better delineation of the laryngeal anatomy than conventional FPD radiography predominantly in patients with moderate-severe cervical spondylosis.