Chest Radiology > Interpretation > Looking


Looking for abnormalities

It is best to do a directed search of the chest film rather than simply gazing at the film.  An abnormality will not likely hit you over the head.  Remember that detail vision is only permitted at the fovea centralis of your retina.  This area contains only cones and is the part that you use to read.  The remainder of the retina helps you to put this detailed portion in context and helps to determine whether this is a saber tooth tiger sneaking up on you.  Therefore, it is best to look for abnormalities and to have a planned search in mind.  Your eye gaze should scan all portions of the film, follow lung/mediastinal interfaces and look again carefully in areas where you know that mistakes are easily made, such as over the spine on the lateral view and in the apex on the PA view.


The above diagrams depict the human eye and light waves hitting the fovea, the area of detailed vision.

 

Stare at the 'X' in the center of the image above.  Note how you cannot read the letters in the corner unless you are looking directly at them (ie unless the letter you are trying to read is hitting your retina at the fovea).

 

 

PA technique for looking at films.  Encompassing the entire lung boundaries (left) , scanning with fovea over each part of lung (right).

 

Lateral scanning technique

 

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