[Doppler transcranial ultrasonography in carotid and vertebral dissections: 36 cases involving angiography].

The aim of this prospective study was to investigate the additional information provided by transcranial pulsed Doppler for the determination of the upper part of dissections of the carotid and vertebral arteries and following-up. Earlier results concerning the role of ultrasound investigations for this indication have been presented elsewhere. Twenty-nine patients were examined (17 females, 12 males; mean age 43 years). All had arterial dissections confirmed by arteriography. There were 24 carotid dissections and 12 vertebral dissections. Investigations were performed during the acute phase and 2 months later. Most of the severe endocranial stenoses were identified by transcranial Doppler: 5 out of 6 severe stenoses of the carotid siphon and 6 out of 7 vertebral stenoses. The haemodynamic effect as measured by sylvian flow was significantly greater (p < 0.01) after a permanent ischaemic event than after temporary events and improved significantly with time (p < 0.008). There was no significant variation in the pulsatility transmission index (PTI), but this index requires a reference artery and is not particularly adapted in cases with bilateral dissection. Collateral perfusion, observed during the acute phase in all cases of occlusion and in 6 of the 8 carotid stenosis, was insufficient in half of the cases. Transcranial pulsed Doppler can be used to guide arteriography and helps determine the length of the dissection. It provides an easy way to assess the haemodynamic consequences of the dissection and is quite useful during follow-up.