Comparison of transcranial Doppler ultrasonography and positron emission tomography using a three-dimensional template of the middle cerebral artery.

Objective: Transcranial Doppler (TCD) measures blood flow velocities (BFV) and is an indirect method of assessing cerebral blood flow (CBF). Positron emission tomography (PET) is a direct method to measure CBF. This study evaluates the correlations between TCD and PET findings Methods: Nine patients with a symptomatic carotid artery stenosis, who underwent CEA, were studied pre- and post-operatively on the ipsi- and contralateral sides. Measurements of the BFV, CO(2) reactivity, CBF, cerebral blood volume (CBV) and mean vascular transit time (MVTT) were performed using a three-dimensional volume of interest (VOI) for the middle cerebral artery (MCA).

Results: CBF in the MCA region, as measured with PET, shows a good correlation with BFV, as measured with TCD, with similar pattern for total, gray and white matter MCA territory (Pearson's correlation coefficients: 0.751, 0.748 and 0.748, respectively). This correlation was found in the pre-operative as well as the post-operative state. No association could be demonstrated between CO(2) reactivity and CBV or (Pearson's correlation coefficients: 0.051 and 0.166, respectively).

Conclusion: With PET, it is possible to create three-dimensional VOI of arterial territories. CBF measured in these VOI seems to correlate with BFV before and after CEA on ipsi- and contralateral sides, while CBV shows no association with pre-operative CO(2) reactivity.