How to Read a Chest X-ray in 10 steps
This is definitely not the ONLY way to read a Chest X-ray but this is the pattern I personally use.
If you can’t remember all the steps the three General steps are:
One big circle around the RIGHT lung (looking at the mediastinum and pleural edge)
One Big Circle around the LEFT Lung (looking at the mediastinum and pleural edge).
Then a zig zag across the lungs comparing side to size.
Step 1: Check all the lines and tubes
Since Lines usually originate outside the body and go centrally, the best place to identify a line is too look around the periphery of the image and try to follow lines as they go centrally (towards the heart, stomach or pleura.
There are bunch of devices to look for in chest x-rays. The main ones to look for:
Vascular: Internal Jugular lines, Subclavian lines, PICC (inserted in the arm)
Pacemakers and Implantable Cardioverter-Defibrillators
Nasogastric/Orogastric Tubes
Endotracheal or Tracheostomy tubes
Gastrostomy/Jejunostomy Tubes
Pleural and Medistinal Drains
Step 2: Take a step back. like literally take a step back from the screen. Are the lungs overall EQUAL in SIZE and DENSITY (brightness)?
This can be a really helpful trick. It can be easy to miss big findings if you are looking too closely at the x-ray, so taking a step back can be really helpful to see differences in size between the two sides of the chest.
If you take a step back and squint you can see the differences in density between the two lungs better.
If one side is darker than the other you have to decide:
Is the Bright side the abnormal side? Or is the Dark Side the abnormal side?
That will lead you down different diagnostic pathways.
Step 3: Right Mediastinal border and diaphragm.
The Right paratracheal stripe outlines the right side of the trachea.
It is created by the interface between the Right Upper lobe and the trachea.
If this line is bowed outwards (Convex), it probably represents something in the mediastinum between the trachea and the lung like a mediastinal mass or a lymph node.
The Azygoesophageal Line is the interface between the esophagus or azygous vein and the right lower lobe.
This line will be affected by an esophageal pathology like an esophageal mass, hiatal hernia, a posterior mediastinal mass like the a neurogenic tumor, or a right lower lobe pathology like a pneumonia.
The right heart border is created by the edge of the heart and the RIGHT MIDDLE LOBE.
So if there is a pneumonia in the right middle lobe, the pneumonia might be very subtle but you will notice that the crispness of the right heart border is gone.
The diaphragm border is created by the interface between bottom segments of the Right Lower Lobe (called the basal segments) and the Diaphragm.
If you don’t clearly see the diaphragm, you might have a pleural effusion, a lower lobe pneumonia, or a combination of both.
The diaphragm on the right is usually higher than the left because of the liver.
Sometimes it can be elevated for a number of reasons including Hepatic Abscess, loculated parapneumonic effusion, or phrenic nerve palsy.
Step 4: Look at the Right Pleural Edge
The Costophrenic angle is where the diaphragm meets the lateral chest wall and the ribs.
The angle it makes should be sharp. If it is rounded there may be a small pleural effusion.
A pleural effusion is free fluid in the pleura, it will create a meniscus sign (the fluid curves upward along the wall like a test tube.
The bigger the amount of fluid in the pleural space increases, the meniscus goes higher up the chest wall.
A loculated pleural effusion may not have this and will have a non gravity dependent shape.
In a SUPINE image, you would see a pneumothorax here as a deep sulcus sign.
In Contrast, the upper pleural edge (lung apex) is where to look for a pneumothorax on an UPRIGHT image.
Other things to look for are pleural masses or calcified plaques which are associated with asbestosis.
Step 5: Left Mediastinal border and diaphragm
Similiar to the Right paratracheal stripe, this left strip outlines the other side of the trachea (left).
It is created by the interface between the Left Upper lobe and the trachea.
If this line is bowed outwards (Convex), it probably represents something in the mediastinum between the trachea and the lung like a mediastinal mass or a lymph node.
The aorta is an important structure to look at.
Look closely at the aortic knob for aortic pathologies such as aneurysm.
THe AP window is the space between the aortic arch and pulmonary artery. This is an important place to look for lymph nodes.
Left heart border is the border of the left heart and the left upper lobe (the lower part- called the lingula because its shaped like a tongue).
IF you lose the left heart border be concerned about lingular pneumonia or pneumonia in the lower part of the left upper lobe.
The left diaphragm border is created by the interface between bottom segments of the Left Lower Lobe (called the basal segments) and the Diaphragm.
If you don’t clearly see the diaphragm, you might have a pleural effusion, a lower lobe pneumonia, or a combination of both.
The diaphragm on the right is usually higher than the left because of the liver.
Sometimes it can be elevated for a number of reasons including Hepatic Abscess, loculated parapneumonic effusion, or phrenic nerve palsy.
Step 6: Left Pleural Space
SImiliar to the other side, the costophrenic angle should be sharp and you should look for a meniscus.
Look for a pneumothorax at the apex in an upright image.
Step 7: Check the lung zones for nodules, consolidation and masses
All you should see in the lungs are branching vessels that gradually get smaller and increased in number as you go to the outer edges of the lungs. Anything other than that is abnormal.
Look for nodules or mass (bright circles)
Look for cysts (dark circles)
Look for consolidation (looks like cotton balls or patchy bright spots or airbronchograms – bright stuff outlining the airways )
Look for edema (large bright areas)
Look for extra lines (kerley B lines)
Step 8: Check the posterior ribs
You want to look at the Ribs look for bony destruction or fractures
Step 9: Check the anterior ribs
The anterior ribs slope downwards and centrally.
Look for bone destruction or fractures.
Step 10: Check the spine, shoulders and clavicles
Look at the clavicles for fractures or destructive lesions.
Look at the shoulders for dislocations and destructive lesions.
Look at the spine for loss of height/fractures and destructive lesions.
The spine should be well defined in a properly exposed chest x-ray. Masses and consolidation may obscure the spinal outlines.
