Apical opacity: a normal finding on posteroanterior chest radiographs

Area of Science:

• Radiology
• Thoracic Imaging
• Vascular Anatomy

Background:

• Chest radiographs are crucial for diagnosing thoracic conditions.
• Anatomical variations can lead to misinterpretation of imaging findings.
• The subclavian artery's location can sometimes mimic other pathologies.

Purpose of the Study:

• To identify the cause of a specific homogeneous oval opacity observed at the lung apices on chest radiographs.
• To correlate radiographic findings with anatomical structures and other imaging modalities.

Main Methods:

• Analysis of 423 posteroanterior chest radiographs from adult patients (aged 21-66 years).
• Evaluation of anatomical data, patient cases with pneumothorax or atherosclerotic calcification.
• Correlation with fluoroscopic and computed tomographic (CT) imaging.

Main Results:

• A homogeneous oval opacity with unsharp margins was identified in 12.8% of right lung apices and 16.8% of left lung apices.
• The opacity's characteristics and location were consistent with the subclavian artery.

Conclusions:

• The apical opacity observed on chest radiographs is consistently produced by the subclavian artery.
• Understanding this finding is important for accurate interpretation of thoracic imaging.
• This study clarifies a common radiographic appearance related to subclavian artery anatomy.