Assessment of chest x-ray technical adequacy (approach)

Described below are some points on an approach to the assessment of the chest x-ray technical adequacy. Rarely, a technically inadequate chest x-ray will prohibit diagnostic interpretation but knowledge of the limitations will impact on diagnostic confidence. 

Exposure/penetration

• assessed by looking at the lower thoracic vertebral bodies, whose outline should just be visible on a PA projection
• the spine should be seen through the heart ¹
• poor penetration: pulmonary vessels and interstitial markings appear more prominent, loss of detail at the lung bases and vertebrae, results in increased density

Inspiratory effort

• anterior aspect of at least six ribs must be noted above the dome of the right diaphragm
• alternatively, posterior aspects of at least eight to nine ribs should be visualized ¹
• poor effort: the cardiac shadow may appear spuriously enlarged, crowding of vessels at lung bases

Rotation

• thoracic spinous processes are equidistant from the medial end of each clavicle on a frontal image
• rotation to the right may cause: pseudo-mediastinal mass, hyperlucency of the right lung
• rotation to the left may cause: aortic arch may appear spuriously enlarged, hyperlucency of the left lung

Magnification 

• films on anteroposterior views slightly magnify the heart ¹

Angulation

• medial ends of the clavicles should be projected over the posterior third or fourth ribs ¹
• clavicles will have a S shape ¹