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[Diagnosis of tracheal instability: spiral CT in inspiratory and expiratory and respiratory cine CT].

PURPOSE
In tracheo- and bronchomalacia, localization and determination of collapse is necessary for planning a surgical procedure. We compared inspiratory and spiral CT, cine CT, and bronchoscopy and evaluated the relevance of each method.


METHODS
Seventeen patients with suspected or verified tracheal stenosis or collapse underwent paired inspiratory and expiratory spiral CT and cine CT during continuous respiration (temporal increment 100 ms). The tracheal cross-sectional area was calculated and compared.


RESULTS
In addition to bronchoscopy, further information concerning localization, extent, collapse, stability of the tracheal wall, distal portions of the stenosis, and extraluminal compressions was obtained. A significantly higher degree of tracheal collapse was seen using cine CT compared to paired spiral CT (p < 0.002). The findings changed the further surgical procedure in 3/17 patients. Further distal stenoses were excluded and bronchoscopy was verified in another 10/17.


CONCLUSION
Paired inspiratory and expiratory spiral CT localizes tracheal stenoses and demonstrates clinically relevant extraluminal compression. Improved evaluation of expiratory collapse and further information of localized tracheal instability is provided by cine CT.