Differential diagnosis of pulmonary infections in immunocompromised patients using high-resolution computed tomography.

Objectives: The aims of this study were to compare the high-resolution computed tomography (HRCT) findings of pulmonary infections in immunocompromised patients and to assess the usefulness of HRCT in the differential diagnosis of these infections.

Methods: A total of 345 immunocompromised patients with pulmonary infections were included in this study. The diagnoses of the patients consisted of bacterial pneumonia (123 cases), pneumocystis pneumonia (PCP) (105 cases), fungal pneumonia (80 cases), tuberculosis (15 cases), cytomegalovirus pneumonia (11 cases), and septic embolism (11 cases). Two chest radiologists retrospectively evaluated the computed tomography (CT) images, which consisted of 22 findings including ground-glass attenuation, consolidation, nodules, and thickening of the bronchial wall and interlobular septum. Associations between the CT criteria and infections were investigated using χ test; multiple logistic regression analyses were conducted to identify the significant indicator for each infection. The area under the curve (AUC) of each model was calculated.

Results: Bronchial wall thickening was a significant indicator for bacterial pneumonia (p = 0.002; odds ratio [OR], 2.341; 95% confidence interval [CI], 1.378-3.978). The presence of a mosaic pattern and the absence of nodules were significant indicators for PCP (p < 0.001; OR, 9.808; 95% CI, 4.883-13.699, and p < 0.001; OR, 6.834; 95% CI, 3.438-13.587, respectively). The presence of nodules was a significant indicator for fungal infection (p = 0.005; OR, 2.531; 95% CI, 1.326-4.828). The AUC for PCP was the highest (0.904).

Conclusions: HRCT findings are potentially useful for the differential diagnosis of some pulmonary infections in immunocompromised patients.

Key Points: • Differential diagnosis of pulmonary infections in immunocompromised patients could be established with the help of high-resolution computed tomography. • Bronchial wall thickening was a significant indicator for bacterial pneumonia. • The presence of a mosaic pattern and the absence of nodules were significant indicators for pneumocystis pneumonia.