T2* measurements of 3-T MRI with ultrashort TEs: Capabilities of pulmonary function assessment and clinical stage classification in smokers

OBJECTIVE. The purpose of this study was to determine the usefulness of MRI with ultrashort TEs on a 3-T system and of thin-section MDCT for pulmonary function assessment and clinical stage classification of chronic obstructive pulmonary disease (COPD) in smokers. SUBJECTS AND METHODS. Forty smokers (24 men and 16 women; mean age ± SD, 68.0 ± 9.3 years) underwent MRI with ultrashort TEs and thin-section MDCT. Pulmonary function testing was also performed to determine the following: the ratio of forced expiratory volume in 1 second to forced vital capacity (percentage predicted) (FEV₁/FVC%), percentage predicted forced expiratory volume in 1 second (%FEV₁), and percentage predicted diffusing capacity of lung for carbon monoxide corrected for alveolar volume (%DLCO/V_A). All subjects were classified into one of four groups as follows: smokers without COPD, with mild COPD, with moderate COPD, and with severe or very severe COPD. T2* maps were expressed using proprietary software. Regional T2* values were determined by region of interest measurements and were averaged to determine a mean T2* value for each subject. CT-based functional lung volume and the ratio of the wall area to the total airway area were also determined. All indexes were statistically correlated with pulmonary function parameters. Then, all indexes were compared among all groups by means of Tukey's honest significance test. RESULTS. All indexes had significant correlation with FEV₁/FVC%, %FEV₁, and % DLCO/V_A (p < 0.05). All indexes except WA% of smokers without COPD and smokers with mild COPD differed significantly from those of smokers with moderate COPD and smokers with severe or very severe COPD (p < 0.05). Moreover, the mean T2* value of the moderate COPD group was significantly different from that of the severe or very severe COPD group (p < 0.05). CONCLUSION. MRI with ultrashort TEs is potentially as useful as quantitatively assessed MDCT for pulmonary function loss assessment and clinical stage classification of COPD in smokers.