Table 3: Comparing those with air trapping verses those without on expiratory images.
| Patients with Air Trapping | Patients without Air Trapping | |
| # of Patients | 49 | 34 |
| % male | 57% | 71% |
| Average age | 59 | 59 |
| Percent with normal initial CT | 42/49 (86%) | 27/34 (79%) |
| Average slice level difference | 32.1 | 25.7 |
| % with Slice level difference greater than or equal 30 | 31/49 (63%) | 14/34 (41%) |