PROMPT early diagnosis of pulmonary embolism is necessary for optimal management, either surgical or medical. Pulmonary embolectomy is now technically feasible and may be lifesaving if performed promptly in correctly selected patients.1,2 Those who might benefit most from embolectomy are the patients in whom a simple, rapid, accurate diagnostic technique is most urgently needed.
The conventional methods of diagnosis include electrocardiography, roentgenograms of the chest, pulmonary angiography, and lung scanning using particulate radioactive substances. Electrocardiography relies on acute changes which indicate a strain on the right side of the heart or recent onset of right bundle branch block.3 The typical "wedge-shaped" area of opacification seen on the chest roentgenogram is rarely present at the time of onset of symptoms, even when massive pulmonary embolism has occurred.4 Pulmonary angiography can be performed by selective arterial catheterization or by direct venous injections. The former requires direct injection through a