Clinical Application of High-Resolution Computed Tomographic Imaging Features of Community-Acquired Pneumonia

Pulmonary invasive fungal disease and bacterial pneumonia: a comparative study with high-resolution CT

BACKGROUND

Early diagnosis of invasive fungal disease (IFD) is challenging. High-resolution computed tomography (CT) may improve IFD diagnosis; however, there are no definitive imaging signs for differentiating between bacterial pneumonia and IFD.

METHODS

We retrospectively evaluated CT images of 208 patients with IFD (n = 102) or bacterial pneumonia (n = 106). We classified pulmonary opacities as consolidations, ground-glass opacities (GGOs), or nodules and recorded the presence of perinodular ground-glass halos, reversed halo sign (RSH), and cavitation (crescent-shaped or not).

RESULTS

Consolidation appeared in 83.3% and 92.5% of patients with IFD and bacterial pneumonia, respectively. Multifocal non-segmental consolidation was more common in IFD (48%) than bacterial pneumonia (22.6%; P < 0.05). Segmental or subsegmental consolidation was more common in bacterial pneumonia (43.4%) than IFD (7.8%; P < 0.01). GGOs and nodules were more common in IFD than bacterial pneumonia (60.8% vs. 24.5% and 54.9% vs. 15.1%, respectively; each P < 0.05). Consolidation combined with GGO, nodules, or both GGO and nodules was more frequent in IFD than in bacterial pneumonia (each P < 0.05). Nodules with halo sign (n = 23) appeared in 22.5% and 3.8% of patients with IFD and bacterial pneumonia, respectively. Nodules with RSH appeared only in IFD, and those with cavitation appeared in 11.8% and 1.9% of patients with IFD and bacterial pneumonia, respectively.

CONCLUSIONS

Consolidation plus GGO and nodules or consolidation plus nodules is suggestive for IFD. Segmental or subsegmental consolidations are more frequent in bacterial pneumonia than in IFD. Large nodules, as well as nodules with halo sign or both small and large nodules, are related to IFD.

Diagnostic Imaging in Sepsis of Pulmonary Origin

Lung infections (community- or hospital-acquired) represent the most common cause for sepsis. Diagnostic imaging plays a crucial role in the initial evaluation of patients with criteria for sepsis and suspected pulmonary infection. In patients with clinical signs and symptoms of respiratory infection, the chest X-ray allows confirming the diagnosis of pneumonia. On the other hand, the chest X-ray can be useful to assess response to treatment (in some patients), define a pattern suggesting specific germs (particularly TB), identify complications (empyema and ARDS), and propose a differential diagnosis.