[Clinicoradiological diagnosis of respiratory infections: estimate of pathogens by radiological findings and the strategy for treatment].

This review discusses the clinicoradiological findings of community-acquired respiratory infections and the treatment strategy for respiratory infections. To make a differential diagnosis between bacterial pneumonia, pneumonia caused by atypical pathogens, and mycobacterial infections, it is very important to analyze the radiological findings of inflammatory lung diseases based on normal antomical structures. If clinicoradiological anlyses could make these differentiations, the appropriate treatment strategy for respiratory infections could be established. To accomplish this, exact orientations of pulmonary lobulus, acinus, and respiratory bronchioles is very important. Then, through analyzing chest CT findings and distribution patterns based on normal anatomical structures, estimation of causative pathogens could be possible. Especially, whether inflammatory exudates could pass Kohn's pores as well as Lambert's channel or not is very important factor to affect radiological findings of several pneumonia (as traditionally called "segmental" and "nonsegmental" distribution). To differentiate infections caused by Mycobacterium tuberculosis from nontuberculous mycobacteria, several important criteria have been demonstrated. Briefly, it has been suggested that Mycobacterium avium complex (MAC) respiratory infection is increasing especially in elderly women without underlying diseases. In MAC respiratory infection, right middle lobe and left lingula are frequently involved and centrilobular nodules and diffuse bronchiectases are characteristic radiological findings. Finally, the role of telithromycin in the treatment of respiratory infections is discussed.