Postgrad Med J doi:10.1136/postgradmedj-2012-131331
  • Images in medicine

Subtle chest x-ray signs of pulmonary thromboembolism: the Palla's and Westermark's signs

  1. Manjunath C Nanjappa
  1. Department of Cardiology, Sri Jayadeva Institute of Cardiovascular Sciences & Research, Bangalore, India
  1. Correspondence to Dr Ravindran Rajendran, Sri Jayadeva Institute of Cardiovascular Sciences and Research, Jaya Nagar 9th Block, BG Road, Bangalore, Karnataka 560069, India; rravi_dr{at}
  • Received 20 July 2012
  • Revised 3 October 2012
  • Accepted 20 November 2012
  • Published Online First 19 December 2012

Palla's sign,1 dilated right descending pulmonary artery >16 mm, and the Westermark's sign,2 focal oligaemia, are useful chest x-ray signs of pulmonary thromboembolism (PTE) even though their sensitivity and specificity are less. Here, we present a case in which PTE was suspected based on these chest x-ray signs.

A 35-year-old male with fever, right thigh pain, breathlessness and cough was considered to have community-acquired pneumonia, and received intravenous antibiotics for 2 days before presenting to us. The ECG (figure 1) showed sinus tachycardia, incomplete right bundle branch block, right ventricular (RV) strain and the characteristic S1Q3T3 pattern. Reviewing the initial chest x-ray (figure 2) done at the primary care setting revealed the subtle but characteristic Palla's sign (RDPA 17 mm) and the Westermark's sign. Echocardiogram (figure 3) showed dilated right atrium, RV and the pulmonary arteries (PA), along with RV dysfunction (see online supplementary video S1). Doppler interrogation showed tricuspid regurgitation with a pulmonary artery systolic pressure (PASP) of 56 mm Hg. Contrast-enhanced CT of the PA (figure 4) confirmed massive pulmonary thromboembolism, and he was given intravenous streptokinase. The patient made a significant symptomatic recovery that was associated with an improvement in RV function and reduction in PASP.

Figure 1

ECG showing sinus tachycardia, right bundle branch block, right ventricular strain, and S1Q3T3 pattern.

Figure 2

Chest x-ray showing dilated right descending pulmonary artery (white arrow), the Palla's sign, and focal oligaemia (between the two white arrow heads), the Westermark's sign.

Figure 3

Apical 4-chamber view showing dilated right atrium and ventricle as compared with that of the left.

Figure 4

Contrast-enhanced CT pulmonary angiogram showing filling defects in the right and left pulmonary arteries.

Chest x-ray is usually normal or non-specific in pulmonary thromboembolism but still, they are very useful in identifying associated conditions and excluding other conditions.3 This case exemplifies the fact that subtle signs of basic investigations when recognised well in time, would help in goal-directed investigations to arrive at the correct diagnosis promptly.


  • Contributors All authors contributed equally.

  • Funding None.

  • Competing interests None.

  • Patient consent Obtained.

  • Provenance and peer review Not commissioned; internally peer reviewed.