Community-acquired pneumonia: a correlative study between chest radiographic and HRCT findings.

PURPOSE: To elucidate what kinds of lesions tend to be overlooked or misinterpreted and why they were overlooked or misinterpreted on chest radiographs in the diagnosis of community-acquired pneumonia (CAP) by comparing radiographic findings with HRCT findings. MATERIALS AND METHODS: In 129 patients with CAP (107 bacterial and 22 atypical) and 105 healthy subjects, the chest radiographic findings were correlated with the HRCT findings. The diagnostic accuracy of each chest radiographic finding was evaluated by comparing it with the HRCT finding. RESULTS: The false negative rate of radiographic interpretation tended to be higher for nodules and thickening of the bronchial wall, especially in patients with atypical pneumonia. The most frequent reason for false negative interpretations of nodules and bronchial wall thickening was the overlapping of these findings with airspace consolidation or ground-glass opacity (GGO). Thin lesions were the most frequent reasons for the false negative interpretation of airspace consolidation and GGO. CONCLUSION: The chest radiographic interpretations of GGO and airspace consolidation were influenced by the thickness of lesions, and those of nodules and thickening of bronchial walls were influenced by coexisting GGO and airspace consolidation and may contribute to a misinterpretation of these lesions and an incorrect diagnosis of CAP.

High-resolution computed tomography findings of influenza virus pneumonia: a comparative study between seasonal and novel (H1N1) influenza virus pneumonia.

PURPOSE: To evaluate the high-resolution computed tomography (HRCT) findings of novel influenza virus (n-IFV) pneumonia and compare them with the findings for seasonal (s-IFV) pneumonia. MATERIALS AND METHODS: We evaluated 29 cases of pure IFV pneumonia that occurred between 1990 and 2010. We evaluated the existence, extent, and patterns of HRCT findings and compared these features between s-IFV and n-IFV. RESULTS: Consolidation was less frequent in s-IFV than in n-IFV (40.0 vs. 84.2%, respectively; p = 0.014). Consolidation with a loss of volume was frequent in n-IFV (62.5%). There was no significant difference in the occurrence of ground-glass opacity (GGO) between s-IFV and n-IFV (100 vs. 84.2%, respectively). GGO with reticular opacities was more frequent in s-IFV than in n-IFV (70.0 vs. 25.0%, respectively; p = 0.024). The frequency of nodules was not significantly different between the two groups. The mosaic pattern was more frequent in s-IFV than in n-IFV patients (80.0 vs. 15.8%, respectively; p = 0.0007). Mucoid impaction was more frequent in patients with n-IFV than with s-IFV (52.6 vs. 10.0%, respectively; p = 0.025). CONCLUSIONS: Consolidation and mucoid impaction were more frequent in n-IFV, whereas GGO with reticular opacities and a mosaic pattern occurred more frequently in s-IFV; otherwise, there were no significant differences between the two groups.