Radiographic features of Mycoplasma pneumoniae pneumonia: differential diagnosis and performance timing

A retrospective review was performed of the CT findings of 64 cases and 68 cases where M. pneumoniae and S. pneumoniae, respectively, were the only pathogen identified by the panel of diagnostic tests used.Of the 64 patients with M. pneumoniae pneumonia, bronchial wall thickening was observed most frequently (81%), followed by centrilobular nodules (78%), ground-glass attenuation (78%), and consolidation (61%). Bronchial wall thickening and centrilobular nodules were observed more often in M. pneumoniae patients than in S. pneumoniae patients (p < 0.0001). The presence of bilateral bronchial wall thickening or centrilobular nodules was only seen in patients with M. pneumoniae pneumonia. Using the scoring system of the Japanese Respiratory Society guidelines and chest CT findings, 97% of M. pneumoniae patients were suspected to be M. pneumoniae pneumonia without serology. When comparing the CT findings between early stage and progressed stage in the same patients with severe pneumonia, the radiographic features of early stage M. pneumoniae pneumonia were not observed clearly in the progressed stage.The present results indicate that the diagnosis of M. pneumoniae pneumonia would appear to be reliable when found with a combination of bronchial wall thickening and centrilobular nodules in the CT findings. However, these CT findings are not observed in progressed severe M. pneumoniae pneumonia patients.Community-acquired pneumonia (CAP) is a common infection, which is sometimes fatal. Despite substantial progress in therapeutic options, CAP remains a significant cause of morbidity and death worldwide (the fourth leading cause of death in Japan). Mycoplasma pneumoniae is one of the most frequent causes of respiratory tract infections, accounting for as many as 10–30% of all cases of CAP [1-3]. Epidemiological studies in Japan have demonstrated that the incidence of M. pneumoniae pneumonia is the second leading pathogen of CAP next to Streptococcus pneumoniae [3,4]. Serolo