Lung CT densitometry in systemic sclerosis: correlation with lung function, exercise testing, and quality of life

Area of Science:

• Radiology
• Pulmonology
• Medical Imaging Analysis

Background:

• Systemic sclerosis (SSc) can cause lung disease, impacting patient health.
• Assessing lung changes in SSc using thin-section CT is crucial for management.
• Current visual assessment methods may lack reproducibility.

Purpose of the Study:

• To compare the reproducibility of lung density histogram analysis versus visual assessment in SSc patients.
• To determine if histogram parameters correlate better with pulmonary function and quality of life.

Main Methods:

• Evaluated intra- and inter-observer reproducibility of visual and densitometric CT analysis in 48 SSc patients using weighted kappa statistics.
• Applied regression analyses to correlate CT measurements with pulmonary function (FRC, FVC, FEV1, Dlco), 6-minute walking test (6MWT), and quality of life (QLQ) parameters.

Main Results:

• Densitometric parameters (mean lung attenuation, skewness, kurtosis) showed higher reproducibility than visual assessment.
• Densitometric measurements correlated better with exercise and quality of life parameters in univariate and multivariate analyses.
• Multivariate analysis showed densitometric parameters predicted FRC, FVC, Dlco, 6MWT, and QLQ (R(2)c = 0.70-0.78), while visual assessment only predicted FRC and FVC (R(2)c = 0.40).

Conclusions:

• Densitometric analysis of lung CT in SSc is more reproducible than visual assessment.
• Histogram parameters offer a closer correlation with pulmonary function, exercise capacity, and quality of life.
• Density histogram analysis is valuable for both cross-sectional and longitudinal studies of lung involvement in SSc.