Right Middle Lobe Atelectasis: Chest Radiographic and CT Appearances Correlating with the Clinical Features

Purpose: To evaluate chest radiographic and CT findings of right middle lobe (RML) atelectasis correlating with the clinical features. Materials and Methods: We reviewed 47 patients with RML atelectasis and classified their chest radiographic findings into four types (Type 1-4) based on the shape of the opacity. The degree of RML atelectasis was classified into three types according to CT findings, namely severe (>90%), moderate (50-90%), and mild (10-50%). Then we correlated them with chest radiographic types and patient\u27s symptoms. Results: In severe atelectasis (n=10), no definite abnormalities were detected on chest radiographs (Type 1). In moderate atelectasis (n=24), 14 cases (58%) showed triangular opacity (Type 2) and nine cases (38%) showed band-like opacity (Type 3) along the right cardiac border. In mild atelectasis (n=13), 11 cases (85%) showed vague opacity at the right lower lung field (Type 4). In severe atelectasis, only one case (10%) had symptoms. In contrast, 14 cases (58%) in moderate atelectasis and six cases (46%) in mild atelectasis had symptoms. Conclusion: Our results indicate that RML atelectasis has a very wide spectrum of imaging finding of chest radiograph and CT, and patient\u27s symptoms are related to the degree of atelectasis