A 34-year-old man presented to the ED with a persistent nonproductive
cough, myalgias, coryza, and a low-grade fever that he had had for
He was otherwise healthy, smoked half a pack of cigarettes per
day, and had no history of asthma, pneumonia, or HIV risk factors.
On examination, he appeared well, and his vital signs were normal
aside from a temperature of 100.4°F. He had a slight
end-expiratory wheeze on lung auscultation. He was treated with
an inhaled bronchodilator. His chest radiograph showed increased
opacity in the lower portions of both lungs and indistinct lung
markings (Figure 1). The lateral portion of the left heart border
The radiograph was interpreted as showing bibasilar infiltrates.
- Do you agree with this interpretation?
Subtle radiographic signs of pneumonia (focal airspace filling)
include indistinct pulmonary vascular markings and obliteration
of a normal lung/soft tissue interface (the silhouette
sign). Such findings seemed to be present in this patient. At the
right base, there is increased opacity and indistinct lung marking.
On the left, there is partial obliteration of the left heart border
However, the patient’s clinical presentation was more
consistent with an upper respiratory tract infection or bronchitis
than a multilobar pneumonia. Furthermore, on the lateral view, there
are no corresponding areas of increased lung opacity either overlying
the heart in the lingula or right middle lobe, or behind the heart
in the right or left lower lobes (Figure 1B). An additional finding on
the PA view is an abnormally increased cardiothoracic ratio—the
width of the heart is greater than half the width of the thorax,
suggesting that the patient has an enlarged heart (Figure 1A).
The disparities between the patient’s clinical and radiographic
findings and between findings on the PA and lateral radiographs
serve as a reminder that a systematic approach to radiograph interpretation
should begin with an assessment of the technical adequacy of the radiographs. In this
case, the x-ray penetration is correct (thoracic vertebral bodies
are visible behind the heart) and the patient has been correctly
positioned without rotation. However, the level of inspiration is
inadequate—only the 9th rib is visible at the right cardiophrenic
sulcus, whereas with a full inspiration, the 10th or 11th rib should
be seen in this location (Figure 2).
Initial PA view—Patient 3.
The vascular markings at both lung bases are crowded and indistinct.
The left heart border is indistinct. The heart appears enlarged
and has a horizontal orientation. These ...
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