2005 Radiology Exam - Thorax Case 2

Objective of the Case
To evaluate the candidate’s ability to identify roentgen signs associated with the heart and create a list of possible causes for those signs.

Information Provided to Candidate
1. Signalment: 5 month old Female Maltese
2. History: Heart murmur detected at 6 weeks of age.
3. Lateral and Dorsoventral radiographs are available.
4. State the radiographic findings.
5. What is your assessment of these findings?
6. Are further imaging studies needed? If so, what are they and why? If no, why not?

See images below. Click to enlarge.

Findings Expected from Candidate
There is severe cardiomegaly present along with an aneurysmal dilation of the descending aorta and the right atrium/auricle. The pulmonary vessels to the caudal lungs are enlarged, blunted and tortuous. The caudal vena cava is greatly distended and there is severe loss of detail within the portion of the abdomen that was imaged. The stomach axis is displaced caudally.

Conclusion Expected from the Candidate
The candidate was expected to conclude that aneurysmal dilation of the descending aorta was suggestive of a patent ductus arteriosus but that the enlarged, tortuous and blunted caudal pulmonary arteries without concurrent pulmonary venous congestion as well as enlargement of the right heart did not support a diagnosis of a typical left-to-right PDA. The were expected to conclude that there was right sided congestive heart failure (enlarged CVC, hepatomegaly and likely ascites) along with probable pulmonary hypertension. The most likely diagnosis was a right-to-left PDA. Additional imaging procedures could include echocardiography or angiocardiography to confirm this suspicion.

Summary of Overall Candidate Performance
Many of the candidates recognized the right sided heart enlargement, right sided heart failure and the aneurysmal dilation. However, they failed to conclude that it was not a typical Left-to-right PDA. They were not able to bring all the roentgen signs together to produce a logical, ranked differential list. They either concluded that is was a left-to-right PDA because of the aneurysmal dilation of the aorta or listed all the possible congenital heart defects even if they did not fit the findings.