Thoracic viscera chest and upper airway: Rad Tech

Radiography of the thoracic viscera and chest are common examinations performed in radiologic practice, and evaluate the mediastinum, lungs, pleural spaces, cardiac silhouette, trachea, and larynx.

Producing diagnostic-quality images requires proper positioning, effective breathing instructions, and careful image evaluation.

As a radiologic technologist, understanding what each projection is designed to show helps you anticipate the anatomy that should be demonstrated, adapt the examination to the patient’s condition, and recognize a diagnostic-quality image before the examination is complete.

Okay, let’s start by reviewing standard projections. The PA chest projection is preferred for a routine examination because it provides a broad view of the lungs and mediastinum while minimizing cardiac magnification.

A patient who is unable to stand may still be able to sit upright for a PA projection, so projection choice should be based on the position the patient can safely maintain.

An AP chest projection is used when the patient can’t face the image receptor or maintain a PA position, as often occurs during portable or bedside imaging.

It demonstrates much of the same anatomy, but the cardiac silhouette and mediastinum may appear larger because they’re farther from the image receptor.

A lateral chest projection provides a 90-degree perspective and places the heart closer to the image receptor. This view can also help localize findings behind the heart or sternum.

When additional evaluation is needed, a horizontal-beam lateral decubitus projection can demonstrate free pleural fluid or air. For a suspected pleural effusion, place the side of interest down so fluid can layer.

For a suspected pneumothorax, place the side of interest facing up so air can rise.

AP and lateral upper-airway projections focus on the air-filled larynx and trachea.

Selecting the appropriate projection depends on the clinical question, departmental protocol, and the position the patient can safely tolerate.

Now, positioning and respiration work together to determine whether the lungs and airway are shown clearly. When the patient’s condition allows, obtain chest images upright to support deeper inspiration and demonstrate possible air-fluid levels.

Proper positioning helps ensure the lung fields, from the pulmonary apices through the costophrenic angles, are included while minimizing rotation, which can distort thoracic anatomy.

For a PA chest, move the shoulders forward to move the scapulae away from the lungs. For a lateral chest, raise the arms so they don't obscure the upper thorax.

Clear breathing instructions are just as important. Chest radiographs are typically obtained at the end of the second full inspiration to maximize lung expansion and improve visualization of the pulmonary anatomy. A clear instruction is: “Take a deep breath in, breathe out, then take another deep breath in and hold it.”

Make the exposure while the patient holds the second inspiration.

For certain clinical indications, an expiration image may also be requested, like when evaluating a suspected small pneumothorax.

For upper-airway projections, exposure during a slow, deep inspiration helps fill the larynx and trachea with air. Confirm the patient can maintain the position and understands breathing instructions before making the exposure. This increases the ability to obtain a clear image on the first attempt.