Prominent cerebral veins on susceptibility-weighted imaging (SWI) in pulmonary embolism

Clinical applications of susceptibility-weighted imaging (SWI) are increasing steadily. The aim of this study is to investigate the appearance of cerebral veins on SWI, which is very sensitive to the deoxyhaemoglobin level in vessels, in pulmonary embolism (PE).

The cranial SWI images of 19 patients with PE and 22 controls from September 2013 through March 2016 were retrospectively examined for the presence of prominent cerebral veins. MRI findings were correlated with blood oxygen levels.

12 of 19 patients with PE had hypoxemia and SWI images of 11 of these hypoxemic patients depicted prominent cerebral veins in the form of increased number, diameter, and elongation. The mean PaO₂ and SaO₂ in these patients were 48.5 ± 9.1 mmHg and 75.2 ± 8.0 %, respectively. There was a significant correlation between the presence of prominent veins on SWI and hypoxemia (p < 0.05). Of the 7 patients with normal blood oxygen pressure and saturation, 1 also showed an augmented appearance of cerebral veins on SWI.

In the presence of neurological symptoms suggestive of an intracranial pathology in patients with PE, a SWI added to the conventional MRI sequences may predict hypoxemia and exclude other intracranial pathologies.

• Patients with PE may exhibit nonspecific symptoms suggestive of an intracranial pathology. • A cerebral venous prominence on SWI should raise the suspicion of hypoxia. • SWI-mIP images intensify the appearance of veins and help distinguish other hypointensities.