The following is a summary of “Histogram-Based Densitometry Index to Assess the Severity of Interstitial Lung Disease in Systemic Sclerosis in Standard and Low-Dose Computed Tomography,” published in the March 2024 issue of Rheumatology by Bruni et al.
Researchers conducted a retrospective study to assess the effectiveness of the recently developed Computerized Integrated Index (CII), which combines mean lung attenuation, skewness, and kurtosis, in evaluating extensive systemic sclerosis–associated interstitial lung disease (SSc-ILD) and predicting mortality using both low-dose 9-slice and standard high-resolution computed tomography (CT) scans.
They evaluated CT scans from patients diagnosed with SSc-ILD using Horos software to calculate standard and reduced CIIs. Extensive ILD was determined according to the Goh staging system. The relationship between CIIs and extensive ILD was examined using a generalized estimating equation regression model, while the predictive performance of CIIs was assessed using the area under the receiver-operation characteristic curve (AUC). The association between CIIs and mortality was investigated through Kaplan-Meier analysis.
The results showed that among 243 patients with available standard and reduced CT scans, 157 CT scans from 119 patients diagnosed with SSc-ILD were part of the derivation cohort. The validation cohort comprised 116 standard CT scans and 175 reduced CT scans. Both CIIs from the standard (OR 0.53, 95% CI 0.37-0.75; AUC 0.77, 95% CI 0.68-0.87) and reduced CT scans (OR 0.54, 95% CI 0.35-0.82; AUC 0.78, 95% CI 0.70-0.87) were significantly linked with extensive ILD. A threshold of CII ≤ −0.96 for standard CT scans and CII ≤ −1.85 for reduced CT scans accurately identified extensive ILD with high sensitivity in both the derivation and validation cohorts. Extensive ILD, as per Goh staging (OR 2.94, 95% CI 1.10-7.82), and standard CII ≤ −0.96 (OR 1.78, 95% CI 1.24-2.56) were significant predictors of mortality. A borderline significance was observed for reduced CII ≤ −1.85 (OR 1.27, 95% CI 0.93-1.75).
Investigators concluded that CII thresholds for extensive ILD identification and mortality prediction were established, potentially aiding clinical practice without radiology expertise.
Source: jrheum.org/content/51/3/270