Chronic obstructive pulmonary disease (COPD) is a common, preventable, and treatable disease that is characterized by respiratory symptoms and airflow limitation that is due to airway and/or alveolar abnormalities usually caused by significant exposure to noxious particles or gases. the CT was used for classification of COPD patients into different phenotypes: phenotype A that has minimal emphysema with or without airway disease, phenotype E that has emphysema without airway disease, and finally phenotype M as a mixed form. The investigators aimed to to identify the phenotypes of COPD using radiologic data obtained by computed tomography. Moreover, this study will be designed to answer the questions about possible correlation between pulmonary function parameters and CT.

Inclusion Criteria:

• All stable COPD patients that lastly confirmed to have the disease based on spirometry and past clinical history according to GOLD (2022).
• Age above 18 years.

Exclusion Criteria:

• COPD patients associated with other chest diseases as collapse
• COPD patients associated with consolidation
• COPD patients unable to perform spirometry

• All stable COPD patients that lastly confirmed to have the disease based on spirometry and past clinical history according to GOLD (2022).and able to perform MSCT