Comparison of transcranial Doppler flow velocity and cerebral blood flow during focal ischemia in rabbits

The predictive value of transcranial Doppler (TCD) cerebral blood dow veloc ity (CBFV) measurements for cerebral blood flow (CBF) calculations in human s is still controversial, and experimental correlative studies are lacking. The aim of the present study was to validate TCD signals of CBFV during fo cal cerebral ischemia, Therefore, CBFV determined in the middle cerebral ar tery (MCA) was compared with values of CBF obtained from autoradiograms of ischemic brain areas, To determine CBFV, a transcranial Doppler ultrasound probe (TCD) adapted to small sample volumes was used in 9 rabbits, CEF was quantified after a final infusion of [C-14]-iodoantipyrine in the same anim als. For focal cerebral ischemia induction, two threads were flushed upward simultaneously into the internal carotid artery, resulting in a flow reduc tion in the ipsilateral MCA. After thread occlusion, mean systolic CBFV in the MCA decreased from 49 +/- 9 cm/s to 22 +/- 3 cm/s, CBF in the caudate n ucleus was reduced (19 +/- 8 mL/100 g/min) compared to the contralateral no nischemic side (52 +/- 18 mL/100 g/min), The decrease in hemispheric CBF co rrelated well with the decrease in both mean systolic (r = 0.97) and diasto lic (r = 0.94) CBFV in the MCA (p < 0.01). The decrease in CBFV determined by transcranial Doppler ultrasound in the MCA appears to reflect the reduct ion in CBF in the affected brain hemisphere and can be used as a quantitati ve in vivo parameter for tissue perfusion. (C) 1999 World Federation for Ul trasound in Medicine & Biology.