Computed tomographic angiography (CTA) is the gold standard diagnostic modality for diagnosing acute pulmonary embolism. Echocardiography should not be used routinely for the diagnosis of acute PE. Echocardiography has a role only in patients with acute shock and high pre-test probability for massive PE, who do not have access to CTA. Indirect echocardiographic signs of acute PE include RV strain (RV dilatation, severe RV free wall hypokinesis or akinesis) and septal flattening, indicating RV pressure and volume overload. These echocardiographic findings are consistent , but not specific to acute cor pulmonale.