Role of Lung Ultrasound in the Assessment of Interstitial Lung Disease in Systemic Sclerosis

Lung ultrasound may be used in the assessment of interstitial lung disease (ILD) in patients with systemic sclerosis (SSc), according to findings from a systematic literature review published in The Journal of Rheumatology. Across 12 published studies, diagnostic results from lung ultrasound were correlated with those of high-resolution computed tomography (HRCT) of the chest; however further research is necessary to confirm the validity and reliability of lung ultrasound for ILD diagnosis.

While HRCT of the chest is highly sensitive for ILD assessment, its high cost and ionizing radiation may result in its limited routine use. Lung ultrasound may be a safer, more cost-effective method of assessing ILD in patients with rheumatic disease.

To assess the validity of lung ultrasound for ILD detection, investigators conducted a systematic review of the PubMed and EMBASE databases for articles published between 1997 and 2017. They performed a detailed search of all available studies according to the guidelines of the Preferred Reporting Items for Systematic Reviews and Meta-Analyses. Articles which reported the use of lung ultrasound to detect ILD in patients with SSc were eligible for inclusion in this review. Studies were screened and selected by 2 independent reviewers; discrepancies were resolved by consensus with a third reviewer. The methodologic quality of selected studies was assessed using the Cochrane Handbook for Systematic Reviews.

Data from 12 of 300 identified publications, each of which were observational, cross-sectional, or descriptive studies, were included in the review. The pooled study cohort included 635 patients with SSc, among whom 82% were women. Participant age ranged from 31.5 to 54.7 years. The primary aim of all selected studies was to determine the correlation between lung ultrasound and HRCT findings.

Lung ultrasound scoring systems varied across studies, though all the studies used B-mode imaging. A total of 11 studies (92%) used HRCT as the gold standard for ILD diagnosis and 4 studies (33.3%) also used the Pulmonary Function Test. All studies demonstrated a correlation between lung ultrasound B-lines and HRCT in the diagnosis of ILD; however, results were not confirmed by multivariate analyses. Overall, 11 studies had low risk for bias, but insufficient data were available to assess ultrasound reliability and reproducibility; 3 studies reported inter- and intraobserver reliability. A few studies explicitly reported on feasibility, though most studies suggested that ultrasound was available in medical centers, accepted by patients and physicians, and was relatively cost-effective.

While the literature suggests that lung ultrasound may have utility in the diagnosis of ILD, further validation is necessary before its widespread use. Overall, while literature review results were “encouraging”, the investigators wrote, “much remains to be done before validating [lung ultrasound] use as an outcome measure in ILD-SSc.”

Reference

Gutierrez M, Soto-Fajardo C, Pineda C, et al. Ultrasound in the assessment of interstitial lung disease in systemic sclerosis: a systematic literature review by the OMERACT ultrasound group. J Rheumatol. 2020;47(7):991-1000.