Computed Tomography Densitometry as a Marker of Disease Severity in SSc-ILD

Computed tomography (CT) densitometry may serve as an additional marker of disease severity in interstitial lung disease (ILD) but its clinical utility needs to be examined further, according to study results published in the Annals of the American Thoracic Society.

Lung involvement is common in systemic sclerosis (SSc), including ILD, which contributes to morbidity and mortality in these patients. Studies have shown that CT scans can provide visual estimates of ILD severity and provide information on disease progression and mortality in patients with SSc-ILD. As there is an urgent need for a specific and sensitive biomarker to describe disease severity and progression in ILD, researchers sought to determine whether CT density-based measurements were more prognostically useful than other measures of outcome in SSc-ILD.

The researchers studied 503 CT scans from 170 patients with SSc-ILD and found that quantitative computed tomography (qCT) high attenuation areas, skewness, kurtosis, and mean lung attenuation were associated with lung function and visual fibrosis scores independent of age, sex, and pack-years using both baseline and change data. They also found that although densitometric qCT was associated with other measurements of ILD severity, density-based qCT measures do not add prognostic information beyond what is obtained using pulmonary function tests. Thus, CT densitometry may be an additional marker of disease severity, but it is prognostically redundant with more readily available measures of ILD severity.

“CT density measurements correlate with physiologic impairment and visual CT scores in patients with SSc-ILD; however, they were not associated with survival independent of changes in pulmonary physiology,” the authors concluded.  “The clinical utility of more sophisticated qCT measures should be explored.”

Disclosure: Several study authors declared affiliations with the pharmaceutical industry. Please see the original reference for a full list of authors’ disclosures.

Reference

Saldana DC, Hague CJ, Murphy D, et al. Association of computed tomography densitometry with disease severity, functional decline, and survival in SSc-ILD [published online March 19, 2020]. Ann Am Thorac Soc. doi:10.1513/AnnalsATS.201910-741OC