Oxygen-enhanced MRI for patients with connective tissue diseases: comparison with thin-section CT of capability for pulmonary functional and disease severity assessment.

PURPOSE

To prospectively and directly compare oxygen-enhanced (O2-enhanced) MRI with thin-section CT for pulmonary functional loss and disease severity assessment in connective tissue disease (CTD) patients with interstitial lung disease (ILD).

MATERIALS AND METHODS

Thin-section CT, O2-enhanced MRI, pulmonary function test and serum KL-6 were administered to 36 CTD patients with ILD (23 men, 13 women; mean age: 63.9 years) and nine CTD patients without ILD (six men, and three women; mean age: 62.0 years). A relative-enhancement ratio (RER) map was generated from O2-enhanced MRI and mean relative enhancement ratio (MRER) for each subject was calculated from all ROI measurements. CT-assessed disease severity was evaluated with a visual scoring system from each of the thin-section CT data. MRER and CT-assessed disease severities of CTD patients with and without ILD were then statistically compared. To assess capability for pulmonary functional loss and disease severity assessment in CTD patients, correlations of MRER and CT-assessed disease severity with pulmonary functional parameters and serum KL-6 in all subjects were statistically determined.

RESULTS

MRER and CT-assessed disease severity showed significant differences between CTD patients with (MRER: 0.15 ± 0.08, CT-assessed disease severity: 13.0 ± 7.4%) and without ILD (MRER: 0.25 ± 0.06, p=0.0011; CT-assessed disease severity: 1.6 ± 1.6%, p<0.0001). MRER and CT-assessed disease severity correlated significantly with pulmonary functional parameters and serum KL-6 in all subjects (0.61 ≤ r ≤ 0.79, p<0.05).

CONCLUSION

O2-enhanced MRI was found to be as useful as thin-section CT for pulmonary functional loss and disease severity assessment of CTD patients with ILD.