Role of transcranial Doppler sonography in the differentiation of multi-infarct and Alzheimer-type dementia.

2505 fast Fourier spectral analysis, but greater reliability has been achieved experimentally using the Wigner method of spectral analysis. 4 Nevertheless, fast Fourier analysis does allow a differentiation that is practically applicable, and appreciation of this enabled us to diagnose three cases of early postoperative carotid thrombosis based on the detection of persistent paniculate embo-lization in the immediate postoperative period. TCD detection of these emboli made possible an early diagnosis of this condition before the development of neurological signs and enabled early operative intervention. This minimized the neurological deficit in two patients and averted deficit in the third, and we believe that this represents an important clinical application of TCD monitoring during CEA. 2 In addition, we were able to determine that the majority of emboli occurring during other stages of the operation were predominantly characteristic of air emboli and not associated with postoperative neurological deficits. 2 In conclusion, we agree with Jansen et al 1 that intraoperative TCD monitoring during CEA is valuable in detecting conditions of inadequate collateral cerebral blood flow and significant episodes of intraoperative embolization. However, we contend that appreciation of the character of the emboli and continuing TCD monitoring into the early postoperative period may be of significant benefit in reducing perioperative mortality and morbidity associated with the operation. AckerstaffRGA. Impact of microembolism and hemodynamic changes in the brain during carotid endarterectomy. The clinical relevance of intraoperative embolisation detected by transcranial Doppler monitoring during carotid endarterectomy: a prospective study in 100 patients. Doppler ultrasound signals from blood borne emboli. Ultrasound Med Biol. In press. Response Gaunt and colleagues 1 report an interesting observation in their series of 100 consecutive patients undergoing CEA. The relation between more than 10 particulate emboli and a significant decrease in postoperative cognitive function is particularly fascinating. The observation is in agreement with the findings reported in a recent article by Pugsley et al, 2 who studied 100 consecutive patients undergoing cardiopulmonary bypass. Their data suggested that neu-ropsychological deficits after cardiopulmonary bypass were related to the number of microemboli delivered during surgery; even more than 1000 microemboli were detected in some patients. Although in a recent series of 301 patients we did not perform neuropsychological function tests, we found a relation between intraoperative focal ischemic symptoms and the occurrence of more than 10 microemboli, especially in the dissection phase of CEA. 3 In our opinion, the analysis of embolic events is …