Table 2.

Radiological characteristics of COPD patients in the included studies

Study number	CT slice thickness	N (with/without bronchiectasis)	Diagnostic criteria of bronchiectasis
1	1 mm collimation at 10 mm intervals	44/39	Method of Goddard et al23
2	1 mm collimation at 10 mm intervals	53/39	1) Lack of tapering of bronchi, 2) dilation of bronchi when the internal diameter was larger than that of the adjacent pulmonary artery, 3) visualization of the peripheral bronchi within 1 cm of the costal pleural surface or adjacent mediastinal pleural surface
3	1 mm collimation at 10 mm intervals	33/13	1) Lack of tapering of bronchi, 2) dilation of bronchi when the internal diameter was larger than that of the adjacent pulmonary artery, 3) visualization of the peripheral bronchi within 1 cm of the costal pleural surface or adjacent mediastinal pleural surface
4	1 mm collimation at 10 mm intervals	115/86	1) Lack of tapering of bronchi, 2) dilation of bronchi when the internal diameter was larger than that of the adjacent pulmonary artery, 3) visualization of the peripheral bronchi within 1 cm of the costal pleural surface or adjacent mediastinal pleural surface
5	1 mm collimation at 10 mm intervals	27/26	Bhalla scoring system24
6	1 mm or 2.5 mm or 5 mm or 7 mm collimation at 10 mm intervals	278/128	1) Lack of tapering of bronchi, 2) dilation of bronchi when the internal diameter was larger than that of the adjacent pulmonary artery, 3) visualization of the peripheral bronchi within 1 cm of the costal pleural surface or adjacent mediastinal pleural surface

Note: Refer Table 1 for details of studies.

Abbreviations: COPD, chronic obstructive pulmonary disease; CT, computed tomography.