Several studies have described the typical imaging features of empyema on CT, including patietal pleural thickening and enhancement,thickening and increased attenuation of the extrapleural fat (Figure 1) and septation and loculation (Figure 2). However, there are further CT imaging features associated with empyema, in particular changes of the visceral pleura (e.g. Figures 3 and 4) and lung parenchyma (e.g. Figure 5 and 6). These features have not previously been reported, or have only been reported in small groups of patients. The aim of this study...

Study Design This was a retrospective analysis of patients participating in the MIST2 study. Patient Population Patients were drawn from the MIST2 stud; a randomised controlled trial of intrapleural fibrinolytic agents. Eligibility There were consistent and robust clinical, biochemical and microbiological criteria for establishing the diagnosis of pleural empyema for patients in the MIST2 study. This study included all patients in the MIST2 study who had a CT scan of the chest performed during the index admission, prior to administration of the study treament, with...

97 patients were included in the study. The prevalence of the features assessed are presented in Table 1. Summary of principle findings: There was low incidence of loculation and visible septation on CT, in concordance with prior studies. A lower incidence of changes to the extrapleural fat were observed than previously documented. We observed almost ubiquitous partietal pleural enhancement and thickening. There was a high incidence of visceral pleural and parenchymal change associated with empyema. However, a significant proportion of patients (37%), did not have...

This study has performed a comprehensive assessment of the prevalence of extrapleural, pleural and parenchymal CT features of associated with empyema, in a large and robustly defined cohort of patients. In addition to previously described extra-pleural and parietal pleural changes associated with empyema, we demonstrated that parenchymal and visceral pleura changes are common. The pattern of features may have implications for diagnosis and management. In particular the wide variation in the pattern of associated parenchymal involvement may imply different disease mechanisms. The high prevalence of...