The dynamics of deglutition during head rotation using dynamic 320‐row area detector computed tomography

OBJECTIVE: We aimed to elucidate the dynamics of deglutition during head rotation by acquiring 320‐row area detector computed tomography (320‐ADCT) images and analyzing deglutition during head rotation. METHODS: This study included 11 patients experiencing globus pharyngeus. A 320‐ADCT was used to acquire images in two types of viscosity (thin and thick), with the head rotated to the left. We measured the movement time of deglutition‐related organs (soft palate, epiglottis, upper esophageal sphincter [UES], and true vocal cords) and pharyngeal volume (bolus ratio at the start of UES opening [Bolus ratio], pharyngeal volume contraction ratio [PVCR], and pharyngeal volume before swallowing [PVBS]). A two‐way analysis of variance was performed for statistical analysis, and all items were compared for significant differences in terms of head rotation and viscosity. EZR was used for all statistical analyses (p‐value <.05). RESULTS: Head rotation significantly accelerated the onset of epiglottis inversion and UES opening compared with no head rotation. The duration of epiglottis inversion with the thin viscosity fluid was significantly longer. The bolus ratio increased significantly with thick viscosity. There was no significant difference in viscosity and head rotation in terms of PVCR. PVBS increased significantly with head rotation. CONCLUSION: The significantly earlier start of epiglottis inversion and UES opening due to head rotation could be caused by: (1) swallowing center; (2) pharyngeal volume; and (3) pharyngeal contraction force. Thus, we plan to further analyze swallowing with head rotation by combining swallowing CT with manometry and examine its relationship with pharyngeal contraction force. LEVEL OF EVIDENCE: 3b