Using FDG PET/CT for assessment of idiopathic pulmonary fibrosis disease activity and prediction of prognosis

<bold>Background:</bold> Idiopathic pulmonary fibrosis (IPF) is a specific form of chronic, progressive fibrosing interstitial pneumonia of unknown cause. Although the overall prognosis is poor, the clinical course varies. Fluorodeoxyglucose (FDG) positron emission tomography (PET) is a valuable tool capable of assessing inflammation, infection, and malignancy. Some studies suggested that FDG PET scans may be helpful in the evaluation of IPF and changes in response after therapy. <bold>Objective:</bold> Our primary objective is to assess the usefulness of FDG PET/computed tomography(CT) in diagnosing and differential diagnosis of IPF. Then, we used FDG PET to assess disease activity and severity, before and after treatment. Finally, no definite prognostic indicator was defined in IPF, so we evaluated the prognostic value of FDG PET in IPF. <bold>Results:</bold> We had included 71 patients (67.2±19.7 years-old, 79% men). After a mean follow-up of 26 months, 27 patients died. In visual analysis, hypermetabolism was found mostly at peripheral and basal portions of bilateral lungs, which was compatible with change of morphology on CT. Our initial findings, analyzed using Kaplan-Meier methodology, indicated a cutoff value for the average of SUVmean at 0.99. This resulted in a borderline difference in all-cause mortality (p=0.065). These preliminary results suggest a potential association between FDG PET/CT findings and mortality in IPF. <bold>Conclusions:</bold> FDG PET has potential in predicting survival in IPF. Further patient enrollment and further analysis would be needed. <table-wrap><object-id>erj;64/suppl_68/PA1643/TB1</object-id><object-id>T1</object-id><object-id>TB1</object-id><table><colgroup><col></col><col></col><col></col></colgroup><tbody><tr><td></td><td>Death</td><td>Survived</td></tr><tr><td>Age</td><td>66</td><td>68</td></tr><tr><td>Survival(months)</td><td>20±17</td><td>30±22</td></tr><tr><td>Early SUVmean</td><td>0.99±0.33</td><td>1.09±0.34</td></tr><tr><td>Delayed SUVmean</td><td>0.99±0.41</td><td>1.03±0.33</td></tr></tbody></table></table-wrap>