FDG PET Imaging in Pneumocystis Pneumonia

Area of Science:

• Medical Imaging
• Infectious Diseases
• Rheumatology

Background:

• Rheumatoid arthritis (RA) patients are susceptible to opportunistic infections like Pneumocystis pneumonia (PCP).
• Diagnosing PCP can be challenging when conventional imaging like CT scans show subtle or equivocal findings.

Observation:

• A 69-year-old woman with RA and pleuritis presented with dyspnea and subtle ground-glass opacities on chest imaging.
• FDG PET revealed pathological uptake in both lungs, suggesting an active inflammatory or infectious process.

Findings:

• Pneumocystis pneumonia was confirmed via positive β-D-glucan assay and PCR for Pneumocystis jirovecii in sputum.
• Post-treatment FDG PET demonstrated resolution of lung uptake, correlating with successful treatment.

Implications:

• FDG PET imaging is a valuable tool for diagnosing PCP in immunocompromised patients, especially when CT findings are inconclusive.
• This case highlights the utility of FDG PET in identifying pulmonary infections in RA patients and assessing treatment response.