PURPOSE: To assess the usefulness of three-dimensional reconstruction image with spiral CT in the evaluation of tracheal stenosis MATERIALS AND METHODS: From March 1997 to October 1998, 19 patients with clinically suspected tracheal stenosis were evaluated with 3D spiral CT imagings. The causes of tracheal stenosis was intubation or tracheostomy (n=15), squamous cell carcinoma of the trachea (n=1), adenoid cystic carcinoma of the trachea (n=2), and extrinsic compression by a right upper lobar bronchogenic carcinoma (n=1). Spiral CT was performed with a slice thickness of 5mm and a table speed of 5mm/sec. The range of scanning was from the epiglottis to the carina. The source images were reconstructed as three dimensional image by the technique of multiplanar reformation (MPR) and shaded surface display (SSD). In the evaluation of location and extent of stenosis, we compared the findings of three-dimensional reconstruction images with those of axial images and endoscopy in all patients. RESULTS: The location of stenosis were as follows: tracheostoma (n=10), upper trachea (n=7), and lower trechea (n=3). In all cases, three dimensional reconstruction images demonstrated the location and extent of stenosis well. No significant differences in diagnostic accuracy were noted among axial images, MPR and SSD images when evaluating the location and extent of stenosis, but three-dimensional reconstruction images showed the extent of stenosis more easily and schematically than axial images. CONCLUSION: Three-dimensional reconstruction image with spiral CT, which shows the extent of stenosis easily and schematically, may be an useful method in the evaluation of tracheal stenosis.