Essential X-Ray Interpretation Skills and Techniques for Nurse Practitioners

Between 1994 and 2015, diagnostic imaging services by nurse practitioners and physician assistants increased by 14,711%. Research consistently shows that nurse practitioners can safely and appropriately request and interpret plain X-rays, particularly in emergency and minor injury settings. The best advice is to be consistent with your approach of evaluating the images you see every single day and as you get used to seeing normal findings, abnormal findings will jump out at you.

Quick and Easy Chest X-Ray Interpretation

One question I constantly get asked as a nurse practitioner is how to get comfortable and confident at x-ray interpretation and identifying chest X-ray findings. Here is the way I recommend you evaluate the chest X-ray to avoid missing subtle findings by using the Alphabet Method.

• Airway: Look for the location and visibility/patency of the trachea and carina. This step is also helpful for identifying if your images properly aligned or off-axis.
• Bones/Breast: Evaluate the cortex of the bones to see if there are any evidence of fracture, healing fracture, and overall exposure of the image. It’s important to recognize that although the breast tissue looks inferior on the image, that is an optical illusion.
• Cardiac Silhouette: Inspect for size, location, and any obliteration of the cardiac margin by adjacent structures. many people who have pneumonia will have an obliteration of the cardiac silhouette known as “silhouette sign”. This helps direct the interpreter of the image as to which lobe of the lung has the pneumonia.
• Diaphragm: Identify the diaphragm bilaterally and no whether one side is higher than the other, or if there is evidence of free air inferior to the diaphragm. Unless a recent abdominal surgery was performed, any evidence of free air should be considered a emergency as it may likely reflect perforated gastric ulcer.
• Extrathoracic Tissue: Consider the size of the bone structure compared to the extra thoracic tissue. If the patient has considerable obesity in the upper torso, expect to find a smaller bony frame of the patient in relationship to their total body mass and skin.
• Fields of the Lung: Evaluate whenever possible both anterior/posterior and lateral imaging to evaluate which lobe may be involved in a consolidation, atelectasis, pneumonia, or nodule. Also evaluate for evidence of Kerley B lines to suggest layering of interstitial fluid and edema.
• Gastric Bubble: Evaluate the gastric bubble for its presence, and also its absence. For patients who are sitting erect, a gastric bubble should be visible.
• Hilum/Mediastinum: Inspect the hilum for evidence of enlarged lymph nodes, masses, overlying lung involvement, and pulmonary edema. also evaluate the mediastinal AM for evidence of aortic enlargement, calcified vasculature, masses, and lymphadenopathy.
• Indwelling Lines/Instrumentation: For hospitalized patients, make sure to include an evaluation for any indwelling lines or tubes used actively in the patients acute care management such as endotracheal tubes, surgical drains, chest tubes, feeding tubes, and central lines.

Interpretation of Orthopedic Extremity X-Rays

Interpretation of orthopedic extremity X-rays involves fewer steps as there is generally not quite so much anatomy to consider compared with the trunk. When interpreting an extremity X-ray, at the most basic level, remember your ABCs.

A – Adequacy and Alignment

The first thing you should analyze with any X-ray is the adequacy of the film. For example, does the image portray the correct side of the body? Is the penetration of the image appropriate? When it comes to orthopedics, always get at least two views of the extremity in question (anterior-posterior and lateral). Finally, assess the alignment of bones. As you look at the relationship of the bones to one another, does anything look out of place?

B – Bones

As you review the films, pay special attention to the cortical outline of each bone and also look for abnormalities in bone density and texture. A breach in the cortical outline signals a fracture whereas changes in bone density may be a sign of a chronic problem like osteopenia or demineralization.

C – Cartilage

While cartilage itself is not readily visible on an X-ray, radiographic imaging does allow for evaluation of joint spaces. Abnormally wide spaces, for example, could signal a ligament injury or distracted fracture. You must also assess the growth plates in your imaging of pediatric patients.

S – Soft Tissue

Finally, check out the soft tissue. Note the size of musculature, any swelling, joint effusion, or other abnormalities like a foreign body. Soft tissue changes like swelling or effusion can clue you in to a problem, such as the “fat pad sign” or “sail sign” which clues you in to a possible intra-articular injury or fracture.

Imaging Distribution Data

When NPs do interpret imaging, the patterns are telling. The following distribution reflects common diagnostic interpretations:

• Chest radiographs: account for 44.57% of interpretations.
• Extremity imaging: account for 34.39% of interpretations.
• Abdominal and pelvic studies: make up 9.04% of interpretations.
• Spine imaging: make up 6.08% of interpretations.

Educational Foundation and Professional Support

Especially when starting out, have an expert to help you go through the image. This may be and on call radiologist, or it may be a peer health care provider with more experience than you. Advanced Pathophysiology provides the disease process foundation that makes imaging findings clinically relevant. You can’t interpret what you don’t understand mechanistically. Evidence-based practice threads through the entire curriculum, because appropriate imaging utilization requires understanding not just what you can see, but when looking is worthwhile.