Dr. Pepe’s Diploma Casebook 165 – SOLVED

Findings: AP chest radiograph shows a poorly defined opacity in the RUL (A, circle).

Axial and coronal enhanced CT show that the opacity corresponds to a tortuous brachiocephalic artery (B and C, arrow). There is no pulmonary infiltrate.

Final diagnosis: Tortuous brachiocephalic artery simulating a pulmonary infiltrate.

The aim of this Diploma is to continue discussing chest imaging in the older population.

Today I will comment about the main manifestations of aging in the mediastinum and heart, discussing variants that may simulate disease, followed by the most common conditions affecting these regions in elderly patients.

NORMAL VARIANTS

The standard PA radiograph in aging adults usually shows a somewhat enlarged mediastinum, due to poor inspiratory effort combined with an elongated aorta and mediastinal fat accumulation (Fig. 1) .

A common variant in older patients is a tortuous brachiocephalic artery, which may project into the lung, simulating a pulmonary lesion (Fig. 2), as was shown in the initial case.

Sometimes the tortuous artery simulates a mediastinal mass. In these cases, the diagnosis is easy because a mediastinal mass pushes the trachea toward the left (Fig. 3A), whereas an elongated artery does not; instead, the associated elongated aorta displaces the trachea to the right (Fig. 3B).

The aorta is elongated in most older adults. A kink in the distal descending aorta often casts a posterior shadow in the lateral view that should not be confused with disease (Fig. 4).

Calcification of the annulus fibrosus of the mitral valve is common in elderly individuals. It does not cause symptoms and should not be confused with other conditions. It has a pathognomonic appearance in the chest radiographs (Fig. 5).

A variant of calcified annulus fibrosus is a condition termed caseous necrosis of the mitral annulus. It appears as an ovoid intracardiac calcification, visible in chest radiographs (Fig. 6) and confirmed with CT. It is also symptomless.

PATHOLOGY

The most common mediastinal pathology in the older population is hiatus hernia, easily identifiable when it contains air. An airless hernia should not be confused with a lower mediastinal mass. The best way to diagnose hiatus hernia is by looking at previous films (Fig. 7). If none are available, a barium swallow is sufficient (Fig. 8).

At times, too much air in a hernia may be misleading, as occurred in the case below, which was initially diagnosed as a possible pneumopericardium (Fig. 9).

Pneumopericardium was suspected. Enhanced CT coronal and sagittal images
show that the apparent pneumopericardium was actually a large hiatus hernia (B and C, arrows). On retrospective review of the patient’s chest radiograph, bowel air can be seen projected over the heart.

Mediastinal mass in patients of advanced age are commonly due to metastasis. Lymphoma is an alternative diagnosis, as around 50% of non-Hodgkin lymphomas occur in patients older than 65 years (Fig. 10).

Differentiating aortic aneurysm from a tortuous aorta is difficult in chest radiographs, because the medial aortic wall is obscured by the mediastinum. Sometimes the inner wall is outlined by air, allowing detection of aortic dilation in the plain film (Fig. 11).

The incidence of atrial fibrillation increases after the age of 65, and up to 9% of octogenarians are affected with this condition. Detecting a prominent left atrium in the chest radiograph of an elderly person should suggest this diagnosis (Fig. 12).

Ventricular aneurysm is a complication of myocardial infarction. In an elderly patient, the aneurysm may calcify and appear as curvilinear calcium projected over the left heart (Fig. 13).

Follow Dr. Pepe’s advice:

1. Tortuous brachiocephalic artery and calcification of the mitral annulus are common variants in persons of advanced age.

2. Hiatus hernia occurs frequently in older individuals.

3. Enlarged left atrium in this age group should raise the possibility of atrial fibrillation.

This is the last case on 2020 and we will be back on January 11, 2021!