Transcranial doppler and (15)O-H2O-positron emission tomography findings in patients with acute brain infarction and middle cerebral artery stenosis.

Transcranial Doppler (TCD) is a useful noninvasive tool for the assessment of the state of main intracranial arteries. Since present techniques for quantitative measurement of regional tissue perfusion (CBF) are invasive and expensive, the question was raised as to whether TCD could also be used to estimate CBF under normal and pathologic conditions. We compared TCD with CBF measurements using (15)O-H2O-positron emission tomography in 26 patients with either acute cerebral infarction or MCA mainstem stenosis and in 6 controls. No correlation was found between any blood velocity parameter and positron emission tomography blood flow values in middle cerebral artery territory neither in cerebrovascular patients nor in controls. We conclude that TCD cannot be used to quantitatively determine regional tissue perfusion. For optimal evaluation of brain blood supply, TCD should be coupled with a CBF imaging technique.