Positron emission tomography in interstitial lung disease

Area of Science:

• Pulmonary Medicine
• Nuclear Medicine
• Radiology

Background:

• Glycolysis rates may indicate inflammation in interstitial lung disease (ILD).
• Idiopathic pulmonary fibrosis (IPF) is primarily fibrotic, unlike some ILDs with significant inflammation.

Purpose of the Study:

• To determine if Positron Emission Tomography (PET) can differentiate IPF from other ILDs based on inflammatory activity.
• To investigate the utility of 18FDG PET in distinguishing fibrotic ILD from inflammatory ILD.

Main Methods:

• Prospective study of 21 patients with diffuse ILD undergoing surgical lung biopsy.
• 18FDG PET scans were performed, and standardized uptake values (SUV) were calculated for lung regions of interest.
• Comparison of SUV between IPF and non-IPF patients.

Main Results:

• No statistically significant difference in SUV was found between IPF and non-IPF patients (P=0.26).
• IPF patients showed a trend towards higher SUV, but this was not statistically significant.
• No significant difference in the SUV ratio between upper and whole lungs was observed between IPF and non-IPF groups (P=0.31).

Conclusions:

• PET imaging with 18FDG does not reliably differentiate IPF from other diffuse interstitial pulmonary processes.
• The inflammatory component of ILD, as assessed by 18FDG uptake, does not distinguish IPF from non-IPF conditions.