Lung density histogram parameters are more reproducible than visual assessment of lung changes in thin-section CT and are more closely related to lung function, exercise capacity, and quality of life in patients with systemic sclerosis (SSc), results of a recent study indicate.
Dr. Gianna Camiciottoli and colleagues from the University of Florence, Italy, evaluated the reproducibility of visual and lung CT densitometric parameters -- such as mean lung attenuation (MLA), skewness, and kurtosis -- in 48 SSc patients examined with CT.

As they report in the March issue of Chest, the investigators found that the intraoperator and interoperator reproducibility of these densitometry parameters were higher than those of visual assessment.

They also assessed the relationship of CT findings to functional parameters, including functional residual capacity (FRC), FVC, FEV1, diffusion capacity of the lung for carbon monoxide (DLCO), six-min walking testing (6MWT), and health-related quality of life questionnaire (QLQ) parameters. Univariate analysis showed that only densitometric measurements were correlated with subscores of exercise and QLQ.

"By multivariate stepwise method, only two functional parameters -- percentage of predicted FRC and percentage of predicted FVC -- predicted independently global visual score, extent, and severity scores, and accounted for approximately 40 per cent of their variance," the researchers write.

"These findings indicate that quantitative CT evaluation would potentially offer an objective and reproducible measure of interstitial lung changes not only in SSc but also in other systemic disease with lung involvement," Dr. Camiciottoli commented to Reuters Health.

Chest 2007;131:672-681.