NONINVASIVE DIAGNOSIS OF PULMONARY-EMBOLISM

Pulmonary embolism (PE) remains a challenging diagnostic problem becau se it mimics other cardiopulmonary disorders. Pulmonary angiography is still the reference standard for diagnosing PE but it is costly, inva sive and not readily available. Non-invasive diagnostic strategies hav e therefore been developed to forego pulmonary angiography in patients suspected of having PE. Ventilation/perfusion lung scanning is, at pr esent, the most widely used non-invasive diagnostic test for PE. A hig h probability ventilation/perfusion scan (segmental or greater perfusi on defects with normal ventilation:) warrants the institution of antic oagulant therapy especially when paired with high clinical suspicion o f PE. Yet, only a minority of patients with confirmed PE have high pro bability ventilation/perfusion scans. Ventilation/perfusion abnormalit ies other than those of the high probability scan should be regarded a s non-diagnostic. Under these circumstances, documentation of deep vei n thrombosis by non-invasive leg testing warrants anticoagulation with out the need for angiography. However, a single negative venous study result does not permit to rule out PE in patients with non-diagnostic ventilation/perfusion scans. Results of a recent prospective study ind icate that accurate diagnosis or exclusion of PE is possible with perf usion lung scanning alone (without ventilation imaging). Combining per fusion lung scanning with clinical assessment helps to restrict the ne ed for angiography to a minority of patients with suspected PE. (C) 19 98 Elsevier Science Ireland Ltd.