VALUE OF TRANSCRANIAL DOPPLER AND DUPLEX SONOGRAPHY - WHEN IS THE METHOD HELPFUL

In recent years transcranial Doppler and duplex sonography have become valuable methods supplementary to extracranial vascular investigation s and especially in intensive care medicine. High grade stenoses and o cclusions of the basal cerebral arteries as well as vascular spasms af ter subarachnoidal haemorrhage can be assessed using well-known Dopple r criteria. Since it can reliably detect significantly enhanced intrac ranial pressure, the Doppler technique can be used also for shortening the waiting time in confirming brain death. The patency of the intrac ranial collateral pathways can be estimated qualitatively, and the CO2 and Diamox test enables quantitative evaluation of cerebral haemodyna mics. Moreover, in future, detecting spontaneous and contrast media-in duced intracranial emboli may contribute to the differentiation of cer ebral ischaemic events.