[Three cases with an extensive lesion in the dependent portion of the lungs diagnosed by chest CT-scan]

Three patients whose lung diseases are diagnosed with CT-scan are reported. A patient showed severe hypoxemia without any abnormal shadow on chest X-P. CT-scan revealed a diffuse and extensive lesion in the dependent portion. We performed his respiratory care in prone position. CT-scan of the second patient with aspiration pneumonia revealed that the lesion existed in the dependent portion. Cardiogenic pulmonary edema of the third patient was found to be distributed mainly in the dependent portion by CT-scan. We consider that CT-scan is useful when chest X-P gives little information.