Topographic evaluation of lateral hypopharyngeal pouches using electron beam tomography.

Background: To evaluate the exact topography of lateral hypopharyngeal pouches using electron beam tomography.

Methods: Seventeen patients, nine female, eight male, aged 28-72 years, who showed lateral hypopharyngeal pouches in the videofluorographic swallowing examination were studied using electron beam tomography. Upon swallowing a 20-ml bolus of water, the region of the thyrohyoid membrane was scanned 20 times per level. Scan parameters: single slice cine mode (exposure time 100 ms, slice thickness 3 mm, 620 mA, 130 KV).

Results: The lateral hypopharyngeal pouches appeared air-filled in the posterior aspect of the thyrohyoid membrane closely attached to the upper horn of the thyroid cartilage, just below the hyoid bone.

Conclusions: With electron beam tomography it was possible to define the topographic location of the pouches more accurately, compared with the prior assumption of position.