Diagnostic value of lung ultrasound vs. quantitative computed tomography in connective tissue disease-associated...

To evaluate the utility of modified lung ultrasound (LUS) and quantitative computed tomography (QCT) in assessing connective tissue disease-associated interstitial lung disease (CTD-ILD) and their correlations with high-resolution computed tomography (HRCT) of the chest.

Between October 2023 and 2024, 77 hospitalized CTD patients (57 CTD-ILD, 20 controls) who had undergone or were scheduled for chest HRCT also received LUS during their hospitalization, ensuring both assessments were completed within 1 week. The LUS and HRCT results were evaluated using modified LUS scores and Warrick scores, respectively. HRCT results were analyzed quantitatively using the "Dexin-FACT" automated analysis software.

Significant differences were observed in all LUS parameters and most QCT parameters between groups (P < 0.01), with significant correlations to ILD severity stratification (P < 0.05). Univariate analysis identified modified LUS scores, LAA_-600~-250%, and the TAV/TNV ratio (the ratio of lumen area to number of blood vessels around the bronchus with a 2 mm diameter in the lower lobe of the lung) as being associated with ILD (P < 0.01). After initial adjustment for age, gender, and BMI, the modified LUS scores demonstrated a significant association with CTD-ILD (OR = 1.94, 95% CI 1.26-2.98). Notably, this association was substantially strengthened in the fully adjusted model controlling for a broader set of clinical confounders, including smoking, disease duration, complications, and CTD type (aOR = 3.62, 95% CI 1.58-8.29), confirming it as the strongest independent predictor compared to LAA_-600~-250% and TAV/TNV. The modified LUS scores showed excellent diagnostic concordance with the Warrick scores (AUC = 0.960), outperforming LAA_-600~-250% (AUC = 0.873).

Modified LUS shows potential as a practical tool for CTD-ILD detection, outperforming QCT parameters in diagnostic agreement with HRCT. These preliminary findings support LUS as an effective adjunct for CTD-ILD assessment. Key Points • Modified lung ultrasound scores outperformed traditional ultrasound metrics in distinguishing connective tissue disease-associated interstitial lung disease severity and showed the strongest predictive association with disease presence. • Significant differences in lung ultrasound and quantitative CT parameters were observed between connective tissue disease-associated interstitial lung disease and non-interstitial lung disease groups, correlating with disease progression and severity stratification. • Modified lung ultrasound demonstrated superior specificity to quantitative CT in detecting connective tissue disease-associated interstitial lung disease, highlighting its potential as a practical, non-invasive adjunct to HRCT.