Page 195 - Clinical Pearls in Cardiology

Radiology 183

• One of the first radiological signs of heart failure is
the upper lobe diversion of blood due to arteriolar
vasoconstriction secondary to alveolar hypoxia. This
vascular redistribution causes the upper lobe
pulmonary arteries and veins to become larger than
their counterparts in the lower lobes. The sign is most
accurate if the upper lobe vessels are greater than
3 mm in diameter in the first intercostal interspace.
It usually occurs at a pulmonary capillary occlusion
pressure of 12 to 19 mm Hg. This phenomenon is
called as the ‘reverse mustache’ sign.
• As the pulmonary capillary occlusion pressure rises
above 19 mm Hg, interstitial edema develops with
bronchial cuffing, and there will be appearance of
horizontal, nonbranching, white lines at the periphery
of the lung fields, just above the costophrenic angle.
These are called as Kerley B lines. They are caused by
edema of the interlobular septa.
• In severe alveolar stage of pulmonary edema, there
is presence of confluent alveolar shadows that spread
out from both hila. This creates a ‘Bat’s wing’
appearance on the chest X-ray.
• Bilateral pleural effusion (initially appears on the
right side).
Note: Chronic eosinophilic pneumonia resembles
tuberculosis in its clinical presentation. Chest
radiographs in this condition show predominantly
peripheral infiltrates. This pattern is classically described
as the photographic negative of acute pulmonary edema.