Unique Anatomical Imaging Findings in Patients With Patulous Eustachian Tube.

OBJECTIVES: The pathophysiology of patulous Eustachian tube (PET) remains poorly understood. This study characterizes nasopharyngeal anatomy to identify features that distinguish PET patients from controls and determine whether anatomical measurements predict symptom laterality. METHODS: Head CT scans from patients with PET diagnosed by Japanese Otologic Society criteria were compared to scans from demographically matched controls. Anatomical features of the Eustachian tube (ET), turbinates, and nasopharynx were measured. PET patients were stratified into bilateral PET, unilateral affected sides, and unilateral unaffected sides. RESULTS: Thirty PET patients (23 unilateral, 7 bilateral) were included. Compared with controls, PET patients demonstrated significantly larger ET orifice diameters (5.61 vs. 4.54 mm, mean difference 1.07 mm, p < 0.001), greater ET patent depth (6.51 vs. 4.76 mm, mean difference 1.74 mm, p < 0.001), larger lateral recess length (6.40 vs. 3.86 mm, mean difference 2.54 mm, p = 0.002), larger lateral recess width (4.37 vs. 2.51 mm, mean difference 1.86 mm, p < 0.001), and greater inferior turbinate-to-ET asymmetry (2.67 vs. 1.24 mm, mean difference 1.43 mm, p < 0.001). Nasopharyngeal dimensions did not differ between groups. No significant differences were identified across groups in the primary analysis. Sensitivity analyses accounting for within-patient correlation demonstrated greater ET patent depth and lateral recess width in symptomatic compared with asymptomatic unilateral PET ears. CONCLUSION: PET patients demonstrate distinct nasopharyngeal anatomy beyond simple ET patency, including enlarged lateral recesses and greater asymmetry in inferior turbinate positioning. However, anatomical measurements poorly predict symptom laterality, indicating that additional physiologic mechanisms not captured by static CT imaging likely contribute to symptom expression. LEVEL OF EVIDENCE: 4.