Objective    To investigate the value of postprocessing techniques of multislice CT for main airway obstructive diseases.     Methods    The images by multiplanar reformation (MPR)

volume rendering (VR) and CT virtual bronchoscopy (CTVB) were.     Results    The shapes of the main airway obstructive diseases were displayed directly in all of the 70 patients using MSCT postprocessing techniques. The percent area stenosis was measured from the MPR images

including 4 mild stenosis (50%)

21 moderate stenosis (50%-75%)

29 severe stenosis (75%)

16 obstructed (100%). The shape

range and degree of main airway obstructive diseases were accurately displayed in MPR images without three dimensional effect. The endoscopic views of stenosis were delineated through CTVB and the three-dimensional images of the pathological changes of main airway obstructive diseases were obtained through VR.     Conclusion    MPR postprocessing techniques can accurately display the main airway obstructive diseases

therefore it is a useful tool in clinical practice. However

the clinical value of CTVB and VR images is limited.