Abstract
Purpose
Noninvasive markers of disease activity in patients with idiopathic pulmonary fibrosis (IPF) are lacking. We performed this study to investigate the reproducibility of pulmonary 18F-FDG PET/CT in patients with IPF.
Methods
The study group comprised 13 patients (11 men, 2 women; mean age 71.1 ± 9.9 years) with IPF recruited for two thoracic 18F-FDG PET/CT studies performed within 2 weeks of each other. All patients were diagnosed with IPF in consensus at multidisciplinary meetings as a result of typical clinical, high-resolution CT and pulmonary function test features. Three methods for evaluating pulmonary 18F-FDG uptake were used. The maximal 18F-FDG pulmonary uptake (SUVmax) in the lungs was determined using manual region-of-interest placement. An 18F-FDG uptake intensity histogram was automatically constructed from segmented lungs to evaluate the distribution of SUVs. Finally, mean SUV was determined for volumes-of-interest in pulmonary regions with interstitial lung changes identified on CT scans. Processing included correction for tissue fraction effects. Bland-Altman analysis was performed and interclass correlation coefficients (ICC) were determined to assess the reproducibility between the first and second PET scans, as well as the level of intraobserver and interobserver agreement.
Results
The mean time between the two scans was 6.3 ± 4.3 days. The interscan ICCs for pulmonary SUVmax analysis and mean SUV corrected for tissue fraction effects were 0.90 and 0.91, respectively. Intensity histograms were different in only 1 of the 13 paired studies. Intraobserver agreement was also excellent (0.80 and 0.85, respectively). Some bias was observed between observers, suggesting that serial studies would benefit from analysis by the same observer.
Conclusion
This study demonstrated that there is excellent short-term reproducibility in pulmonary 18F-FDG uptake in patients with IPF.
Noninvasive markers of disease activity in patients with idiopathic pulmonary fibrosis (IPF) are lacking. We performed this study to investigate the reproducibility of pulmonary 18F-FDG PET/CT in patients with IPF.
Methods
The study group comprised 13 patients (11 men, 2 women; mean age 71.1 ± 9.9 years) with IPF recruited for two thoracic 18F-FDG PET/CT studies performed within 2 weeks of each other. All patients were diagnosed with IPF in consensus at multidisciplinary meetings as a result of typical clinical, high-resolution CT and pulmonary function test features. Three methods for evaluating pulmonary 18F-FDG uptake were used. The maximal 18F-FDG pulmonary uptake (SUVmax) in the lungs was determined using manual region-of-interest placement. An 18F-FDG uptake intensity histogram was automatically constructed from segmented lungs to evaluate the distribution of SUVs. Finally, mean SUV was determined for volumes-of-interest in pulmonary regions with interstitial lung changes identified on CT scans. Processing included correction for tissue fraction effects. Bland-Altman analysis was performed and interclass correlation coefficients (ICC) were determined to assess the reproducibility between the first and second PET scans, as well as the level of intraobserver and interobserver agreement.
Results
The mean time between the two scans was 6.3 ± 4.3 days. The interscan ICCs for pulmonary SUVmax analysis and mean SUV corrected for tissue fraction effects were 0.90 and 0.91, respectively. Intensity histograms were different in only 1 of the 13 paired studies. Intraobserver agreement was also excellent (0.80 and 0.85, respectively). Some bias was observed between observers, suggesting that serial studies would benefit from analysis by the same observer.
Conclusion
This study demonstrated that there is excellent short-term reproducibility in pulmonary 18F-FDG uptake in patients with IPF.
| Original language | English |
|---|---|
| Pages (from-to) | 521-528 |
| Number of pages | 8 |
| Journal | European Journal of Nuclear Medicine and Molecular Imaging |
| Volume | 39 |
| Issue number | 3 |
| Early online date | 30 Nov 2011 |
| DOIs | |
| Publication status | Published - Mar 2012 |
Bibliographical note
AcknowledgementsA large proportion of funding for this work was provided by GSK. This work was undertaken at UCLH/UCL, which received a proportion of the funding from the UK Department of Health NIHR Biomedical Research Centres funding scheme. We acknowledge the input from GSK (CRT115549) Research and Developments in Stevenage, UK, and the GSK CRAFT consortium.
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