Diaphragmatic Muscle Thickness: A Complementary Tool in Assessing Lung Involvement in Patients with Systemic...

Area of Science:

• Radiology
• Pulmonology
• Rheumatology

Background:

• Systemic sclerosis (SSc) is an autoimmune disease where interstitial lung disease (ILD) is a primary cause of mortality.
• Diaphragmatic muscle impairment is an understudied factor potentially contributing to respiratory dysfunction in SSc patients.

Purpose of the Study:

• To evaluate diaphragmatic thickness in SSc-ILD patients using High-Resolution Computed Tomography (HRCT).
• To determine correlations between diaphragmatic thickness, disease severity, and clinical outcomes in SSc-ILD.

Main Methods:

• A multicentric retrospective observational study included 161 participants (69 SSc-ILD, 92 controls).
• Diaphragmatic thickness was measured on HRCT by two independent radiologists.
• Clinical and functional parameters (FVC, DLCO, 6MWT) were analyzed.

Main Results:

• SSc-ILD patients exhibited significantly thinner left hemidiaphragms compared to controls (p=0.004).
• Right hemidiaphragm thinning showed a trend towards reduction (p=0.072) and correlated with lower Forced Vital Capacity (FVC).
• Left diaphragm cut-off (≤3.115 mm) showed modest discriminative performance (AUC=0.635).

Conclusions:

• HRCT-measured left hemidiaphragm thickness is reduced in SSc-ILD patients.
• Diaphragm thickness may serve as a supplementary marker for respiratory function assessment in SSc-ILD.
• Prospective studies are needed to confirm causality and prognostic value.