Cerebral blood flow in cerebral vascular disease: assessment by colour Doppler, transcranial Doppler and SPECT

Summary

Since 1988 we have been using SPECT 99Tc-HMPAO, Duplex scanner (DS), colour Doppler imaging (CDI) and transcranial Doppler (TCD) to assess arterial stenosis or occlusion, collateral circulation and blood supply adequacy. In cerebral vascular disease, clinical features do not often predict the presence or degree of vessel lesions, but correlate well with the integrated morphological and functional data about cerebral circulation and perfusion. DS and CDI have a high specificity in detecting atherosclerotic disease (97%). TCD has a high sensitivity for intracranial vascular pathology. SPECT HMPAO is more useful than TCD for imaging brain tissue damage; it shows hypoperfusion in about 70% of transient ischaemic attacks and agrees with the improvement or worsening of the symptoms. These functional images and cerebral artery velocity patterns appear to be important tools in understanding and evaluating brain damage caused by embolism and by haemodynamic failure.