Role and sensitivity of Positron Emission Tomography with [18F]Fluorodeoxyglucose in diagnosis and follow-up of patients affected by chronic pulmonary aspergillosis (CPA)

Abstract

Introduction: PET/CT is considered as a powerful tool to diagnose, stage, and monitor patients with a variety of diseases. In this study, we assessed the sensitivity and the degree of agreement between 18F-FDG PET/CT and serological tests in diagnosis and follow-up of patients affected by chronic pulmonary aspergillosis (CPA). Methods: Thirty-seven adult patients (21 males and 16 females) affected by CPA were recruited during the study period (2010 - 2017). At the time of first diagnosis, we compared sensitivity of 18F-FDG PET/CT and serologic tests (i.e., identification of Aspergillus-specific IgE and IgG antibodies using IFA and ELISA). 12 months after the treatment, we repeated tests only in patients with possible active disease to make a comparison between serological tests and 18F-FDG PET/CT. Sensitivity was calculated as the proportion of positive results obtained with the index test among cases. The agreement between diagnostic techniques was assessed using the Kappa coefficient. The level of significance was set at 5% (P < 0.05). Results: At the time of first diagnosis, agreement between 18F-FDG PET/CT and serologic tests was ‘almost perfect’ (88%, Kappa = 0.846, P < 0.05), whereas it was ‘good’ at 12 months follow-up (81%, Kappa = 0.684, P < 0.05). At first diagnosis, serological test had a higher sensitivity (94.59%, 95% Confidence Interval [CI] 81.81% to 99.34%) in comparison with 18F-FDG PET/CT (83.78%, 95% CI 67.99% to 93.81%). Conversely, at 12-month follow-up, 18F-FDG PET/CT showed higher sensitivity (93.75, 95% CI 69.77% to 99.84%) than serological test group (75%, 95% CI 47.62% to 92.73%). Discussion and Conclusion: Our findings demonstrate that both methods are suitable and have almost equivalent sensitivity in diagnosis and follow-up of patients affected by CPA with active disease. 18F-FDG PET/CT scan is a reliable support tool for clinical and serological data in the diagnosis and follow-up of aspergillosis infection, providing additional information on metabolic activity, accurate anatomic localization and extent of disease.

Keywords

• Diagnosis pulmonary aspergillosis
• Positron Emission Tomography
• sensitivity
• serological test