[How reliable is the measurement of tracheal stenosis by means of computed tomography?].

BACKGROUND: A reliable preoperative appraisal of laryngotracheal stenoses is necessary for airway surgery as well as stent implantation. Through progress of modern radiological modalities, particularly the computer tomography (CT), sectional image data and three dimensional airway reconstruction gain increasingly in meaning in Otorhinolaryngology.

METHODS: The aim of this study was to evaluate the reliability of this modern CT data in comparison to laser scan data. For this purpose deep frozen pig tracheal segments were prepared and examined by means of helical CT at different CT sets. Subsequently the measurement of the tracheal lumen employing a highly precise laser scanner was performed.

RESULTS: As a result we found that a CT slice thickness of 3 mm, a maximal pitch of 1.5 as well as the application of the so-called: edge enhancing modus seems to be the best compromise between the precision of CT airway measurement on one hand and breath-hold time for patient and total X-ray dose on the other hand.

CONCLUSIONS: The ENT specialist requires a good cooperation with the radiologist for the measurement of laryngotracheal stenoses using CT scans. We recommend the working out of standard parameters for respiratory tract-CTs.