[Pulmonary embolism: the techniques, indications and diagnostic impact of lower limb investigations].

The non-invasive diagnosis of pulmonary emboli is based, in part, on evidencing a deep venous thrombosis (TVP-DVT); one of the principal features of thromboembolic disease with pulmonary emboli. Ultrasonic venograms have been introduced as the best non-invasive morphological examination for the diagnosis of DVT. Its sensitivity in subjects suspected of having pulmonary emboli (but having no frank signs of DVT) is inferior to that observed in cases where there is a clinical suspicion of DVT. On the other hand, only 70 per cent of subjects having pulmonary emboli have a DVT of the lower limbs on phlebography. For these reasons, only a positive ultrasonogram has any value in the diagnostic process as a negative ultrasonic venogram does not allow a pulmonary embolus to be excluded with certainty. A search for a DVT of the lower limbs should thus be integrated into the diagnostic approach which is both reasoned and rigorous in a search for pulmonary emboli.