engleski

Functional transcranial doppler and technetium-99m-hexamethypropyleneamine oxime single photon emission computed tomography in evaluation of neurovascular coupling

INTRODUCTION: Functional Transcranial Doppler (fTCD) is method for assessment of cerebral blood flow velocity (BFV) changes coupled to brain activity. The study objective was to quantify BF responses in healthy subjects during computer-game play, which contained visuospatial and visuomotor elements. We tested reliability and validity of fTCD for evaluating neurovascular coupling (NC) in correlation with single photon emission computed tomography (SPECT). Technetium-99m-HMPAO-SPECT provides reliable regional cerebral blood flow (rCBF) information as response to brain activity. MATERIALS AND METHODS: Ten healthy right-handed subjects (6 women and 4 men ; average+/-SD age, 28, 1 +/-5, 34 years) underwent fTCD and SPECT measurement of rCBF during rest condition and during activation task. BFV changes were measured simultaneously in both middle cerebral arteries (MCA). The BFV percentage increase (BFVI%) compared with baseline was calculated. SPECT measurement of rCBF in parietal regions was performed by regions of interest (ROI) analysis. Relative perfusion increase was calculated as percentage change of baseline value. RESULTS: Playing game induced mean BFVI% in left and right MCAs (average+/-SD) ; 7, 74 +/- 2, 47% and 10, 79+/-2, 46%, respectively), (Figure 1). Relative perfusion increases in right parietal region were (average+/-SD ; 0, 956+/-0, 016 versus 0, 985+/-0, 019 count/second, rest versus stimulation, respectively) in all patients (Figure 2). The percentage increase in cerebral perfusion during activation in right parietal region versus left parietal region was (average+/-SD ; 4, 584+/-2, 041% vs 3, 474+/-2, 310%). CONCLUSION: Functional TCD showed moderate BFVI% in both MCAs indicating that BFV changes were coupled to brain activation. SPECT showed slight rCBF percentage increase in right parietal lobes reflecting the level of neuronal activity during mental activity. Both techniques might be useful in quantification of neurovascular coupling.

functional TCD; technetium SPECT; neurovascular coupling

DOI: 10.1111/j.1468-1331.2004.00919.x