This work was aimed at optimizing the spiral CT technique in studying the trachea to obtain multiplanar reconstructions with high diagnostic yield. The authors tried to identify an image reconstruction technique, on both the coronal and the sagittal planes, to visualize the whole trachea on a single image in each patient. Twenty patients, 15 with pathologic tracheal involvement and 5 with pulmonary lesions with no tracheal involvement, were examined with a Somatom Plus CT unit (spiral technique: 120 kV, 210 mA, 5-mm slices, 5-mm/s table feed and 24-s scanning time). Multiplanar reconstructions were obtained on the oblique plane, identified by three axial reference scans at different levels. The whole trachea was reconstructed on a single image in 100% of cases on the coronal plane and in 95% of cases on the sagittal plane. Image quality was good in 16 patients and acceptable in 4. The authors stress the value of spiral CT multiplanar images when the reconstruction plane lies in the tracheal lumen on both the coronal and the sagittal planes.