SPONTANEOUS DISSECTIONS OF THE INTERNAL CAROTID-ARTERY - APPEARANCES ON COLOR DOPPLER ULTRASOUND

Spontaneous dissection of the internal carotid artery (ICA) is an unus ual finding. We present an analysis of five patients (aged 40-60 years ) with ICA dissections, describing the various flow patterns detected on colour Doppler ultrasound. Particular attention was paid to the pre sence of a dual lumen, the direction of flow in the false lumen and th e velocity/spectral broadening of the Doppler trace obtained from the true and false lumens. Four different patterns were observed. Narrowin g of the true lumen by the false lumen thrombus was seen in two cases with a low velocity Doppler waveform: three cases had a patent false l umen (''double lumen'' pattern); the direction of flow in the patent f alse lumen varied from being (i) forward, (ii) reversed and (iii) bidi rectional. The flow dynamics in carotid dissections are complex and ar e primarily dependent upon the presence of thrombus within the false l umen, the entry and exit flaps if the false lumen is patent. the motio n of the flap wall and the extent of the dissection. They illustrate t he diverse nature of the disease and Doppler ultrasound plays an impor tant role in the Imaging of ICA dissections.