I would like to start 2019 with a new section, called “The art of interpretation”.
Interpreting the chest radiograph is becoming a lost art and I would like to help you improve your skills in this area. With this in mind, I plan to show radiographs with interesting findings and analyze the steps that will lead to a correct evaluation of these findings.
That said, here is the first case: the chest radiographs of a 50-year-old man with liver cirrhosis and bloody vomiting.
What do you see and what would your diagnosis be?
Check the images and come back on Friday to see the answer!
Click here to see the solution
Interpreting a chest radiograph involves three basic steps:
1 – Gather information. Examine the radiographs carefully and collect all the pertinent information. Remember that overlooking visible findings is the main cause of errors.
2 – Analyze the findings. Once collected, the findings should be properly evaluated and an opinion should be offered.
3 – Decide on the next step to reach the diagnosis.
Step 1. Visible findings in the PA radiograph:
1. Rounded retrocardiac opacity (A, red arrow)
2. Downward displacement of the left hilum (A, white arrow), accompanied by verticalization of the left main bronchus
3. Vertical line in the left lower lung, which corresponds to the major fissure displaced medially (A, yellow arrow)
4. Blunting of the left costophrenic angle, accompanied by slight pleural thickening (A, green arrows)
Visible findings in the lateral chest radiograph:
1. Posterior location of the nodular opacity, which has a poorly-defined outline (B, red arrow)
2. Blunting of the posterior costophrenic angle, which confirms the findings in the PA view
3. Posterior displacement of the major fissure (B, yellow arrow), confirming the findings in the PA view
Step 2. Analysis of the findings
1. Loss of volume of the LLL, indicated by downward displacement of the left hilum together with medial displacement of the major fissure
2. Intrapulmonary location of the LLL nodule, indicated by its poorly-defined outline in the lateral view
3. Chronic pleural disease, suggested by blunting of the costophrenic angle and pleural thickening
Summing up all the findings, the basal intrapulmonary nodular opacity with loss of volume of the LLL and pleural thickening are highly suggestive of rounded atelectasis.
Once rounded atelectasis is suspected in the chest radiograph, the best procedure to confirm it is chest CT, which shows:
1. Curving of the LLL vessels leading into the rounded atelectasis (A and B, red arrows)
2. Air bronchogram in the periphery of the nodule (B and C, blue arrows)
Also note displacement of the major fissure (A-C, yellow arrows) and thickened pleura (A-C, asterisks)
Rounded atelectasis is not an uncommon cause of a nodular lesion of the lung. It occurs secondary to spiral folding of the lung parenchyma when fixed by thickened pleura. The consequence is a peripheral rounded opacity, which should not be confused with a true nodule. It is usually asymptomatic and mainly associated with asbestos-related disease.
The imaging appearance of rounded atelectasis is very characteristic. The typical features include:
1. Peripheral lung nodule
2. Pleural thickening
3. Loss of volume of the affected lobe
4. Curving of vessels and bronchi on CT
5. Air bronchogram in the periphery of the nodule on CT
These features are well demonstrated in the case shown.
Remember that rounded atelectasis occurs as a consequence of pleural disease. Lack of pleural thickening should lead us away from this diagnosis and suggest other possibilities.
To emphasize the typical findings of rounded atelectasis I am showing two more cases.
Asymptomatic 49-year-old man with rounded atelectasis. Note the peripheral nodular component (B, white arrow), inner displacement of the left major fissure indicating loss of LLL volume (A, white arrows), and pleural thickening (A and B, red arrows).
CT shows pathognomonic signs: curving of the vessels into the atelectatic nodule (C and D, white arrows), which also shows an air bronchogram in the proximal portion (D, blue arrows). Note the pleural thickening (C and D, red arrows).
Rounded atelectasis in a 63-year-old man with an indeterminate nodule in the chest films (A and B, white arrows). The minor fissure is elevated, indicating RUL volume loss (A, red arrow).
CT images show that the nodule represents rounded atelectasis. Note the peripheral localization with associated pleural thickening (C and D, red arrows), the curving vessels (C and D white arrows), and the air bronchogram in the proximal portion (D, blue arrows).
Dr. Pepe’s teaching points:
Remember the basic steps of interpretation:
1. Gather information
2. Analyze the findings
3. Recommend the next procedure