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.
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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
See also
Systematic chest radiograph assessment:
assessment of the technical adequacy