Capability of differentiating smokers with normal pulmonary function from COPD patients: a comparison of CT pulmonary volume analysis and MR perfusion imaging.

OBJECTIVE

To compare CT volume analysis with MR perfusion imaging in differentiating smokers with normal pulmonary function (controls) from COPD patients.

METHODS

Sixty-two COPD patients and 17 controls were included. The total lung volume (TLV), total emphysema volume (TEV) and emphysema index (EI) were quantified by CT. MR perfusion evaluated positive enhancement integral (PEI), maximum slope of increase (MSI), maximum slope of decrease (MSD), signal enhancement ratio (SER) and signal intensity ratio (RSI) of perfusion defects to normal lung.

RESULTS

There were 19 class I, 17 class II, 14 class III and 12 class IV COPD patients. No differences were observed in TLV, TEV and EI between control and class I COPD. The control was different from class II, III and IV COPD in TEV and EI. The control was different from each class of COPD in RSI, MSI, PEI and MSD. Differences were found in RSI between class I and III, I and IV, and II and IV COPD. Amongst controls, MR detected perfusion defects more frequently than CT detected emphysema.

CONCLUSIONS

Compared with CT, MR perfusion imaging shows higher potential to distinguish controls from mild COPD and appears more sensitive in identifying abnormalities amongst smokers with normal pulmonary function (controls).

KEY POINTS: • Detailed information is needed to diagnose chronic obstructive pulmonary disease. • High-resolution CT provides detailed anatomical and quantitative information. • Magnetic resonance imaging is demonstrating increasing potential in pulmonary function imaging. • MR perfusion can distinguish mild COPD patients from controls. • MRI appears more sensitive than CT in identifying early abnormalities amongst controls.