How to Read Chest X-ray Results (with Pictures)

2024 Author: Jason Gerald | [email protected]. Last modified: 2023-12-16 10:50

You may have seen the results of a chest X-ray (chest radiograph), or you may even have had the test yourself. Have you ever wondered how to read the results of a chest X-ray test? When viewing a radiograph, remember that it is a 2-dimensional representation of a 3-dimensional object. The height and width of each object are the same, but you won't be able to see the thickness. The left side of the film sheet shows the right side of the patient's body, and vice versa. Air appears black, fat is gray, soft tissue and water are light shades of gray, and bone and metal are white. The denser the tissue, the paler the color will be on the X-ray. Dense tissue is pale opaque on film, whereas less dense tissue is transparent and dark in color on film.

Step

Part 1 of 2: Conducting Initial Checks

Step 1. Check the patient's name

Before doing anything else, make sure that you see the correct results of the chest X-ray. This seems obvious, but when you're stressed and feeling pressured, you may be missing some basics. Studying a wrong chest X-ray is a waste of time, when you actually want to save time.

Step 2. Study the patient's medical history

As you get ready to read the results of the x-ray test, make sure that you have all the pertinent information about the patient, including their age and gender, and their medical history. Remember to compare it with the results of the previous X-ray test, if any.

Step 3. Read the date of the test

Make special notes when comparing the results of the test with the results of previous tests (always pay attention to the results of previous tests, if any). Recorded test dates have important context for translating any results.

Part 2 of 2: Assessing Film Quality

Step 1. Check that the film is taken at full breath

The results of the chest X-ray are usually taken when the patient is in a state of full breathing in the respiratory cycle, a condition which in layman's terms is called breathing in. This has an important effect on the quality of the x-ray film. When an X-ray is beamed through the front of the chest against the film, the part of the rib closest to the film is the back rib, so it will be the most visible part. You should be able to see all ten back ribs if the film was shot on a full breath.

If you see the front 6 ribs as well, this means the film is of a very good standard of quality

Step 2. Check the lighting

An overexposed film will appear darker than normal, and cause the individual areas to appear blurry. Pay attention to the part of the body between the vertebrae on the X-ray that is done correctly.

• A low-light chest X-ray cannot distinguish the spine of the body from the space between the vertebrae.
• The film is definitely underexposed if you can't see the spine on the thorax.
• An overexposed film shows the space between the vertebrae very sharply.

Step 3. Find the signs of rotation

If the patient is not fully leaning on the X-ray, you may see a rotation or twisting in the results. If this happens, the mediastinum may look abnormal. You can look for rotation by looking at the head of the clavicular and thoracic spine.

• Check that the thoracic spine is straight in the position in the middle of the sternum and between the clavicular.
• Check that the clavicular is at the same level.

Identifying and Positioning X-Rays

1. Look for position clues. The next thing to do is to identify the position of the X-ray and arrange it properly. Check the position instructions, which are printed on the sheet of film. “L” means left position, and “R” means right position. “PA” means the front (posteroanterior) position, and “AP” means the back (anteroposterior) position, etc. Note the patient's body position: supine (supine), upright (standing upright), lateral (side), decubitus (lean). Check and remember each position on this chest X-ray.

   

2. Adjust the X-ray position of the back (PA) and the lateral side. The chest X-ray usually consists of a PA section and a lateral section of film, which will be read together. Align the films so they can be seen, as if the patient were in front of you, so that the right side of the patient is facing your left.

   

   • If there is an old film, you should hang it close together.
   • The term “postroanterior” (PA) refers to the direction the x-ray beam traverses the patient's body from posterior to anterior, i.e. from back to front.
   • The term “anteroposterior” (AP) refers to the direction the x-ray beam travels across the patient's body from anterior to posterior, i.e. from front to back.
   • The position of the lateral chest radiograph is taken from the left side of the patient's chest against the X-ray test kit.
   • The oblique (tilt) position uses a rotated angle of view between the regular front view and the lateral position. This position is useful for locating the wound and removing overlapping structures.

3. Understand the position of the AP X-ray. Sometimes an AP X-ray is done, but usually only in patients who are so ill that they are unable to stand up straight for a PA X-ray. AP radiographs are generally taken close to the film, as compared to PA radiographs. Distance reduces the effects of different lighting and structural magnification on parts that are closer to the x-ray device, such as the heart.

   

   • Because the AP radiograph is taken at close range, it looks larger and less sharp than on regular PA film.
   • AP films can cause the heart to appear larger and the mediastium to appear wider.

4. Determine if the film is taken from the lateral decubitus position (lying on the side). An X-ray from this position is taken with the patient's body lying on the side. This position helps examine certain suspected fluid problems (fluid in the pleural cavity), and shows whether the fluid flow is slow or fast. You can view a non-dependent hemithorax to determine if a pneumothorax is present, which is a collection of air or gas in the pleural space.

   

   • The dependent lung will appear denser, due to atelectasis (condition of non-functioning of the lung due to obstruction of the bronchi or bronchioles) from the weight of the mediastinum that puts pressure on it.
   • If this is not the case, this is an indication of trapped air.

5. Align the left and right x-rays. You need to make sure you see the test results correctly. Do this easily and quickly by looking for gastric bubbles. The bubble should be on the left.

   

   • Check gas level and location of gastric bubbles.
   • Normal gas bubbles can also be seen in the corners or folds of the liver and spleen in the colon.

Analyzing Images

1. Start with an overview. Before you move on to focusing on specific details, it's good to have an overview. Key points that you may accidentally miss can change the normal benchmarks you use as a point of reference when studying the details. Starting with an overview also sharpens your sensitivity to look for the specifics. X-ray technicians often use what's called the ABCDE method: check the airway (A), bones (B), cardiac silhouette (C), diaphragm (D) and lung spaces and everything others/ lung field and everything else (E).

   

2. Check for other parts such as tubes, intravenous (IV) lines, EKG instructions, pacemakers, surgical clips, or drainage lines.

   

3. Check the airway. Check to see if the patient's airway is clear or occult. For example, in the case of a pneumothorax, the airways diverge away from the problem side. Find the “carina”, which is the point where the trachea branches to the right and left of the main bronchus.

   

4. Examine the bones. Look for signs of fracture, injury, or deformity. Note the overall size, shape, and contour of each bone, as well as density or mineralization (osteopenic bone appears thin and slightly opaque), thickness of cortex compared to medullary cavity, trabecular pattern, presence of erosion, fracture, lytic or blastic areas. Look for sores, which appear light-colored and sclerotic.

   

   • A bone is clearly injured if it shows less density (looks darker), which may appear to be pushing outward compared to other surrounding bone.
   • A bone is clearly sclerotic if it shows a higher density than normal (appears whiter).
   • In the joints, observe joint space narrowing, widening, calcification of the cartilage, air in the joint space, and abnormal fat pads.

5. Observe the heart silhouette markings. The silhouette sign is essentially an absence of a silhouette or loss of the lung/soft tissue interface, which occurs after a mass or large volume of water is present in the lungs. Look at the size of the heart shadow (the white space represents the heart, which is located between the lungs). The silhouette of a normal heart occupies less than half the width of the chest.

   

   The heart appears water bottle shaped on a regular PA film, with abnormal pericardial fluid outflow. Perform an ultrasound or “Computed Tomography” (CT) of the chest to confirm your interpretation

6. Check the diaphragm. Look for a flat or protruding diaphragm. A flat diaphragm may be an indication of emphysema. A protruding diaphragm may be an indication of an area of airspace consolidation (as in the case of pneumonia), which makes the lower lungs different in terms of tissue density compared to the abdomen.

   

   • The right diaphragm is usually higher than the left, because the liver is below the right diaphragm.
   • Also observe the costophrenic angle (which should be sharp) if there is a blunt part, as this may indicate a fluid drainage disorder (ie fluid buildup in that area).

7. Check the heart. Check the edges of the heart, as the outline of the silhouette should be sharp. Observe if there is a bright spot that blurs the outline of the heart, in the right and left middle lobes of the lingula pneumonia, for example. Also observe the external soft tissue for any abnormalities.

   

   • A heart with a diameter greater than half the diameter of the thorax is an enlarged heart.
   • Watch for swollen lymph nodes, look for subcutaneous emphysema (air density under the skin), and other injuries.

8. Check the lung spaces. Start by examining the symmetry and searching each major plane for any abnormal stretch or density. Try to train your eyes to peer through your heart and upper abdomen toward the back of your lungs. You should also check for vascularity and the presence of masses or nodules.

   

   • Examine the lung spaces and look for signs of infiltration, fluid, or air in the bronchi (bronchogram).
   • If fluid, blood, mucus, tumor or other tissue fills the air sacs, the lungs will appear transparent (bright), with less pronounced interstitial markings.

9. Love it. Look for swelling and mass at the hila from both sides of the lung. From the front view, most of the hila shadows represent the left and right pulmonary arteries. The pulmonary artery is always more prominent than the right, so the left hilum appears higher.

   

   Look for calcification of the lymph nodes at the hilum, which may be due to a previous tuberculosis infection

Tips

• Practice will eventually allow you to understand the X-ray test results perfectly. Study and read some chest X-rays so that you become more proficient at reading them.
• When checking for rotation, observe the clavicular head in relation to the spinous process. The distance between the two should be the same.
• The most important rule in reading a chest X-ray is to start with general observations, then move on to specific details.
• Follow a systematic approach to reading X-rays, to make sure you don't miss anything.
• Always compare the x-rays you read with previous ones, if available. *This comparison will help you detect new diseases and evaluate changes.
• The heart size should be less than 50% of the chest diameter on the PA film.

Related article

• Controlling Tuberculosis
• Diagnosing Asthma
• Diagnosing COPD

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