Non-invasive studies of the extra-cranial cerebral arteries: indication for angiography and operation

During recent years, the risk involved in cerebral angiography has been considerably reduced. However, in our patient group this risk was still almost as high as that involved in operation. Non-invasive examination by means of the ultrasonic Doppler procedure has been improved with a resulting success rate of over 95%. Color coding stored in a computer program with the "Echoflow"-procedure allows for demonstration of the neck vessels giving an indication of the degree of stenosis. By this method, pictures of document quality are provided which can also be obtained by inexperienced examiners and interpreted more easily than curve registrations of the acoustic signals. In comparison with angiography, the Echoflow method was less sensitive than the conventional ultrasonic Doppler procedure especially in cases of low-degree stenosis of the internal carotid artery. Nevertheless, in 2.7% of the cases, a correct Echoflow diagnosis could be confirmed during operation where angiography had not shown the changes correctly. As the Echoflow procedure does not give sufficient information on intracranial pathology, we have so far dropped angiography in emergency cases only when establishing the indication for operation; however, in follow-up examinations this method is used exclusively instead of angiography.