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 hypophar yngeal pouches in the videofluorographic swallowing examination were s tudied using electron beam tomography. Upon swallowing a 20-ml bolus o f water, the region of the thyrohyoid membrane was scanned 20 times pe r level. Scan parameters: single slice cine mode (exposure time 100 ms , slice thickness 3 mm, 620 mA, 130 KV). Results: The lateral hypophar yngeal pouches appeared air-filled in the posterior aspect of the thyr ohyoid membrane closely attached to the upper horn of the thyroid cart ilage, just below the hyoid bone. Conclusions: With electron beam tomo graphy it was possible to define the topographic location of the pouch es more accurately, compared with the prior assumption of position.