PET/CT and inflammatory mediators in systemic sclerosis-associated interstitial lung disease

Area of Science:

• Radiology and Nuclear Medicine
• Pulmonology
• Rheumatology

Background:

• Systemic sclerosis (SSc) is an autoimmune disease that can affect the lungs, leading to interstitial lung disease (ILD).
• High-resolution computed tomography (HRCT) is used to assess lung changes in SSc-ILD.
• 18F-FDG PET/CT measures metabolic activity, potentially reflecting inflammation in ILD.

Purpose of the Study:

• To correlate HRCT findings with pulmonary metabolic activity using 18F-FDG PET/CT.
• To examine the relationship between HRCT patterns, metabolic activity, and inflammatory markers in SSc-ILD patients.

Main Methods:

• Cross-sectional study of 23 adult SSc-ILD patients.
• Utilized 18F-FDG PET/CT and HRCT imaging.
• Measured serum chemokine levels, clinical data, and pulmonary function.

Main Results:

• Nonspecific interstitial pneumonia pattern was common (82.6%).
• Serum levels of CCL2, a marker of fibroblast activity, correlated with ground-glass opacity (GGO) on HRCT (p=0.007).
• 18F-FDG PET/CT showed metabolic activity across all HRCT patterns, but could not differentiate intensity.

Conclusions:

• 18F-FDG PET/CT may not distinguish metabolic activity intensity across HRCT patterns in chronic SSc-ILD.
• The CCL2 and GGO correlation suggests fibroblast activity in these lung regions.
• Further investigation of CCL2 expression in SSc-ILD lung tissue is warranted.