C pneumoniae pneumonia demonstrates a wide spectrum of thin-section CT findings that are similar to those of S pneumoniae pneumonia and M pneumoniae pneumonia; airway dilatation and bronchovascular thickening were significantly more frequent in patients with C pneumoniae pneumonia.

This article reviews roles of imaging examinations in the management of community-acquired pneumonia (CAP), imaging diagnosis of specific CAP and discrimination between CAP and noninfectious diseases. Chest radiography is usually enough to confirm the diagnosis of CAP, whereas computed tomography is required to suggest specific pathogens and to discriminate from noninfectious diseases. Mycoplasma pneumoniae pneumonia, tuberculosis, Pneumocystis jirovecii pneumonia and some cases of viral pneumonia sometimes show specific imaging findings. Peribronchial nodules, especially tree-in-bud appearance, are fairly specific for infection. Evidences of organization, such as concavity of the opacities, traction bronchiectasis, visualization of air bronchograms over the entire length of the bronchi, or mild parenchymal distortion are suggestive of organizing pneumonia. We will introduce tips to effectively make use of imaging examinations in the management of CAP. Key words: Community-acquired pneumonia; Computed tomography; Infection; Pneumonia; Lung disease Core tip: This review article discusses imaging diagnosis of community-acquired pneumonia (CAP). As imaging findings of CAP are considered nonspecific, this topic is rarely focused on in radiology journals. However, we believe that imaging examinations contribute much more than generally considered if detailed evaluation of the imaging findings is made. In this article, we will introduce tips to effectively make use of imaging examinations in the management of CAP. Nambu A, Ozawa K, Kobayashi N, Tago M. Imaging of community-acquired pneumonia: Roles of imaging examinations, imaging diagnosis of specific pathogens and discrimination from noninfectious diseases. World J Radiol 2014; 6(10): 779-793 Available from:

Purpose To correlate currently available quantitative CT measurements for airway disease with physiological indices and the body-mass index, airflow obstruction, dyspnea, and exercise capacity (BODE) index in patients with chronic obstructive pulmonary disease (COPD). Materials and methods This study was approved by our institutional review board (IRB number 2778). Written informed consent was obtained from all subjects. The subjects included 188 current and former cigarette smokers from the COPDGene cohort who underwent inspiratory and expiratory CT and also had physiological measurements for the evaluation of airflow limitation, including FEF25–75%, airway resistance (Raw), and specific airway conductance (sGaw). The BODE index was used as the index of clinical symptoms. Quantitative CT measures included % low attenuation areas [% voxels ≤ 950 Hounsfield unit (HU) on inspiratory CT, %LAA−950ins], percent gas trapping (% voxels ≤ −856 HU on expiratory CT, %LAA−856exp), relative inspiratory to expiratory volume change of voxels with attenuation values from −856 to −950 HU [Relative Volume Change (RVC)−856 to −950], expiratory to inspiratory ratio of mean lung density (E/I-ratio MLD), Pi10, and airway wall thickness (WT), luminal diameter (LD) and airway wall area percent (WA%) in the segmental, subsegmental and subsubsegmental bronchi on inspiratory CT. Correlation coefficients were calculated between the QCT measurements and physiological measurements in all subjects and in the subjects with mild emphysema (%LAA−950ins <10%). Univariate and multiple variable analysis for the BODE index were also performed. Adjustments were made for age, gender, smoking pack years, FEF25–75%, Raw, and sGaw. Results Quantitative CT measurements had significant correlations with physiological indices. Among them, E/I-ratio MLD had the strongest correlations with FEF25–75% (r = −0.648, <0.001) and sGaw (r = −0.624, <0.001) while in the subjects with mild emphysema subsegmental WA% and segmental WA% had the strongest correlation with FEF25–75% (r = −0.669, <0.001) and sGaw (r = −0.638, <0.001), respectively. The multiple variable analyses showed that RVC−856 to −950 was an independent predictor of the BODE index showing the highest R2 (0.468) as an independent variable among the QCT measurements. Conclusion Quantitative CT measurements of gas trapping such as E/I-ratioMLD, correlate better with physiological indices for airway disease than those of airway such as WA% or LD. In mild emphysema, however, quantitative CT measurements of airway correlate better with the physiological indices. RVC−856 to −950 is a predictor of the BODE index.

BackgroundAs stereotactic body radiotherapy (SBRT) is a highly dose-dense radiotherapy, adverse events of neighboring normal tissues are a major concern. This study thus aimed to clarify the frequency and degree of clinical symptoms in patients with rib fractures after SBRT for primary lung cancer and to reveal risk factors for rib fracture. Appropriate α/β ratios for discriminating between fracture and non-fracture groups were also investigated.MethodsBetween November 2001 and April 2009, 177 patients who had undergone SBRT were evaluated for clinical symptoms and underwent follow-up thin-section computed tomography (CT). The time of rib fracture appearance was also assessed. Cox proportional hazard modeling was performed to identify risk factors for rib fracture, using independent variables of age, sex, maximum tumor diameter, radiotherapeutic method and tumor-chest wall distance. Dosimetric details were analyzed for 26 patients with and 22 randomly-sampled patients without rib fracture. Biologically effective dose (BED) was calculated with a range of α/β ratios (1–10 Gy). Receiver operating characteristics analysis was used to define the most appropriate α/β ratio.ResultsRib fracture was found on follow-up thin-section CT in 41 patients. The frequency of chest wall pain in patients with rib fracture was 34.1% (14/41), and was classified as Grade 1 or 2. Significant risk factors for rib fracture were smaller tumor-chest wall distance and female sex. Area under the curve was maximal for BED at an α/β ratio of 8 Gy.ConclusionsRib fracture is frequently seen on CT after SBRT for lung cancer. Small tumor-chest wall distance and female sex are risk factors for rib fracture. However, clinical symptoms are infrequent and generally mild. When using BED analysis, an α/β ratio of 8 Gy appears most effective for discriminating between fracture and non-fracture patients.