In a secondary analysis of the Multi-centre Intra-pleural Sepsis Trial (MIST) 2 trial of patients with laboratory proven pleural infection, the combination of parietal pleural enhancement and pleural thickening was seen in 98.7% of patients (95% CI, 92.8%-99.8%) on pleural-phase contrast-enhanced CT [15]. The presence of pleural enhancement with pleural gas/microbubbles [16] or larger pleural effusion size [17] also boosts the accuracy for identifying parapneumonic effusions requiring thoracentesis [16,17]. Parapneumonic effusions <2.5 cm in anteroposterior (AP) dimension can often be managed without thoracentesis [18]. From a technical perspective, acquiring the CT scan 60 seconds after the IV contrast bolus optimizes visualization of the pleura [19,20]. CT Chest Without and With IV Contrast There is no relevant literature to support the use of CT chest without and with IV contrast in the initial imaging of recent pneumonia with suspected parapneumonic effusion or empyema. CT Chest Without IV Contrast There is no relevant literature to support the use of CT chest without IV contrast in the initial imaging of recent pneumonia with suspected parapneumonic effusion or empyema. If a noncontrast CT is obtained, 4 out of 5 chest CT findings most commonly associated with the diagnosis of empyema in a recent meta-analysis may be ascertained without IV contrast: pleural thickening (sensitivity 68%, 95% CI, 56%-77%; specificity 87%; 95% CI, 80%-92%), loculation (sensitivity 52%, 95% CI, 44%-59%; specificity 89%; 95% CI, 82%-94%), fat thickening (sensitivity 53%, 95% CI, 47%-60%; specificity 91%; 95% CI, 82%-96%), and fat stranding (sensitivity 39%, 95% CI, 32%- 48%; specificity 97%; 95% CI, 94%-98%) [14]. Of note, these pooled sensitivities and specificities include CT chest with IV contrast or CT chest without IV contrast.
Workup of Pleural Effusion or Pleural Disease. In a secondary analysis of the Multi-centre Intra-pleural Sepsis Trial (MIST) 2 trial of patients with laboratory proven pleural infection, the combination of parietal pleural enhancement and pleural thickening was seen in 98.7% of patients (95% CI, 92.8%-99.8%) on pleural-phase contrast-enhanced CT [15]. The presence of pleural enhancement with pleural gas/microbubbles [16] or larger pleural effusion size [17] also boosts the accuracy for identifying parapneumonic effusions requiring thoracentesis [16,17]. Parapneumonic effusions <2.5 cm in anteroposterior (AP) dimension can often be managed without thoracentesis [18]. From a technical perspective, acquiring the CT scan 60 seconds after the IV contrast bolus optimizes visualization of the pleura [19,20]. CT Chest Without and With IV Contrast There is no relevant literature to support the use of CT chest without and with IV contrast in the initial imaging of recent pneumonia with suspected parapneumonic effusion or empyema. CT Chest Without IV Contrast There is no relevant literature to support the use of CT chest without IV contrast in the initial imaging of recent pneumonia with suspected parapneumonic effusion or empyema. If a noncontrast CT is obtained, 4 out of 5 chest CT findings most commonly associated with the diagnosis of empyema in a recent meta-analysis may be ascertained without IV contrast: pleural thickening (sensitivity 68%, 95% CI, 56%-77%; specificity 87%; 95% CI, 80%-92%), loculation (sensitivity 52%, 95% CI, 44%-59%; specificity 89%; 95% CI, 82%-94%), fat thickening (sensitivity 53%, 95% CI, 47%-60%; specificity 91%; 95% CI, 82%-96%), and fat stranding (sensitivity 39%, 95% CI, 32%- 48%; specificity 97%; 95% CI, 94%-98%) [14]. Of note, these pooled sensitivities and specificities include CT chest with IV contrast or CT chest without IV contrast.