Abstract: Objective To analyze the photographic character of tree in bud at pulmonary tuberculosis.Methods To check 216 pulmonary tuberculosis patients with spiral CT and statistic the formation and location of tree in bud at various tuberculosis.Results The rates of tree in bud sign at smear positive and cavity pulmonary tuberculosis were 84.5% and 92.3% respectively.The rate in tuberculoma was 9.1%. The occurrence frequency of tree in bud in cavity pulmonary tuberculosis which located in down lobe was 87.5%.The occurrence rate of opposite lung was 60.3%.Conclusion Tree in bud sign is the character photographic of pulmonary tuberculosis which spread through airway.It shows different formation and distribution during different period of tuberculosis development.

Key words: Pulmonary tuberculosis/diagnosis, Tography,X-ray Computed